diff --git a/gclient_scm.py b/gclient_scm.py
index e8c1711f8..85bb0eca0 100644
--- a/gclient_scm.py
+++ b/gclient_scm.py
@@ -85,6 +85,8 @@ def CreateSCM(url, root_dir=None, relpath=None):
   scm_name = GetScmName(url)
   if not scm_name in SCM_MAP:
     raise gclient_utils.Error('No SCM found for url %s' % url)
+  if not gclient_utils.FindCommandExecutable(scm_name):
+    raise gclient_utils.Error('%s command not found' % scm_name)
   return SCM_MAP[scm_name](url, root_dir, relpath)
 
 
diff --git a/gclient_utils.py b/gclient_utils.py
index 35f8b3bf4..ac5f0b4f3 100644
--- a/gclient_utils.py
+++ b/gclient_utils.py
@@ -193,6 +193,16 @@ def safe_makedirs(tree):
         raise
 
 
+def FindCommandExecutable(cmd):
+  """Finds the specified |cmd| in $PATH and returns its path.  Returns None
+  if it's not found."""
+  for path in os.environ['PATH'].split(os.pathsep):
+    full_path = os.path.join(path, cmd)
+    if os.path.isfile(full_path) and os.access(full_path, os.X_OK):
+      return full_path
+  return None
+
+
 def CheckCallAndFilterAndHeader(args, always=False, **kwargs):
   """Adds 'header' support to CheckCallAndFilter.
 
diff --git a/tests/gclient_scm_test.py b/tests/gclient_scm_test.py
index 94ab4203a..c83822ce2 100755
--- a/tests/gclient_scm_test.py
+++ b/tests/gclient_scm_test.py
@@ -55,6 +55,7 @@ class BaseTestCase(GCBaseTestCase, SuperMoxTestBase):
         'CheckCallAndFilterAndHeader')
     self.mox.StubOutWithMock(gclient_scm.gclient_utils, 'FileRead')
     self.mox.StubOutWithMock(gclient_scm.gclient_utils, 'FileWrite')
+    self.mox.StubOutWithMock(gclient_scm.gclient_utils, 'FindCommandExecutable')
     self.mox.StubOutWithMock(gclient_scm.gclient_utils, 'RemoveDirectory')
     self.mox.StubOutWithMock(gclient_scm.scm.SVN, 'Capture')
     self.mox.StubOutWithMock(gclient_scm.scm.SVN, '_CaptureInfo')
@@ -111,6 +112,9 @@ class SVNWrapperTestCase(BaseTestCase):
         'url',
     ]
 
+    gclient_scm.gclient_utils.FindCommandExecutable('svn').AndReturn("./svn")
+    self.mox.ReplayAll()
+
     # If you add a member, be sure to add the relevant test!
     self.compareMembers(self._scm_wrapper('svn://a'), members)
 
@@ -122,6 +126,7 @@ class SVNWrapperTestCase(BaseTestCase):
   def testSVNFullUrlForRelativeUrl(self):
     self.url = 'svn://a/b/c/d'
 
+    gclient_scm.gclient_utils.FindCommandExecutable('svn').AndReturn("./svn")
     self.mox.ReplayAll()
     scm = self._scm_wrapper(url=self.url, root_dir=self.root_dir,
                             relpath=self.relpath)
@@ -130,6 +135,7 @@ class SVNWrapperTestCase(BaseTestCase):
   def testGITFullUrlForRelativeUrl(self):
     self.url = 'git://a/b/c/d'
 
+    gclient_scm.gclient_utils.FindCommandExecutable('git').AndReturn("./git")
     self.mox.ReplayAll()
     scm = self._scm_wrapper(url=self.url, root_dir=self.root_dir,
                             relpath=self.relpath)
@@ -138,6 +144,7 @@ class SVNWrapperTestCase(BaseTestCase):
   def testGITFakeHttpUrl(self):
     self.url = 'git+http://foo'
 
+    gclient_scm.gclient_utils.FindCommandExecutable('git').AndReturn("./git")
     self.mox.ReplayAll()
     scm = self._scm_wrapper(url=self.url, root_dir=self.root_dir,
                             relpath=self.relpath)
@@ -146,6 +153,7 @@ class SVNWrapperTestCase(BaseTestCase):
   def testGITFakeHttpsUrl(self):
     self.url = 'git+https://foo'
 
+    gclient_scm.gclient_utils.FindCommandExecutable('git').AndReturn("./git")
     self.mox.ReplayAll()
     scm = self._scm_wrapper(url=self.url, root_dir=self.root_dir,
                             relpath=self.relpath)
@@ -155,6 +163,7 @@ class SVNWrapperTestCase(BaseTestCase):
     options = self.Options(verbose=False)
     gclient_scm.os.path.exists(join(self.base_path, '.git')).AndReturn(False)
     gclient_scm.os.path.exists(join(self.base_path, '.hg')).AndReturn(False)
+    gclient_scm.gclient_utils.FindCommandExecutable('svn').AndReturn("./svn")
 
     self.mox.ReplayAll()
     scm = self._scm_wrapper(url=self.url, root_dir=self.root_dir,
@@ -169,6 +178,7 @@ class SVNWrapperTestCase(BaseTestCase):
 
   def testRevertMissing(self):
     options = self.Options(verbose=True)
+    gclient_scm.gclient_utils.FindCommandExecutable('svn').AndReturn("./svn")
     gclient_scm.os.path.isdir(self.base_path).AndReturn(False)
     gclient_scm.os.path.exists(self.base_path).AndReturn(False)
     gclient_scm.scm.SVN.Capture(['--version'], None
@@ -211,6 +221,7 @@ class SVNWrapperTestCase(BaseTestCase):
     gclient_scm.os.path.exists(parent).AndReturn(False)
     gclient_scm.os.makedirs(parent)
     gclient_scm.os.path.exists(parent).AndReturn(True)
+    gclient_scm.gclient_utils.FindCommandExecutable('svn').AndReturn("./svn")
     files_list = self.mox.CreateMockAnything()
     gclient_scm.scm.SVN.Capture(['--version'], None
         ).AndReturn('svn, version 1.6')
@@ -230,6 +241,7 @@ class SVNWrapperTestCase(BaseTestCase):
 
   def testRevertNone(self):
     options = self.Options(verbose=True)
+    gclient_scm.gclient_utils.FindCommandExecutable('svn').AndReturn("./svn")
     gclient_scm.os.path.isdir(self.base_path).AndReturn(True)
     gclient_scm.os.path.isdir(join(self.base_path, '.svn')).AndReturn(True)
     gclient_scm.scm.SVN.CaptureStatus(None, self.base_path).AndReturn([])
@@ -250,6 +262,7 @@ class SVNWrapperTestCase(BaseTestCase):
     options = self.Options(verbose=True)
     gclient_scm.os.path.isdir(self.base_path).AndReturn(True)
     gclient_scm.os.path.isdir(join(self.base_path, '.svn')).AndReturn(True)
+    gclient_scm.gclient_utils.FindCommandExecutable('svn').AndReturn("./svn")
     items = [
       ('~      ', 'a'),
     ]
@@ -279,6 +292,7 @@ class SVNWrapperTestCase(BaseTestCase):
     options = self.Options(verbose=True)
     gclient_scm.os.path.isdir(self.base_path).AndReturn(True)
     gclient_scm.os.path.isdir(join(self.base_path, '.svn')).AndReturn(True)
+    gclient_scm.gclient_utils.FindCommandExecutable('svn').AndReturn("./svn")
     items = [
       ('~      ', '.'),
     ]
@@ -302,6 +316,7 @@ class SVNWrapperTestCase(BaseTestCase):
 
   def testStatus(self):
     options = self.Options(verbose=True)
+    gclient_scm.gclient_utils.FindCommandExecutable('svn').AndReturn("./svn")
     gclient_scm.os.path.isdir(self.base_path).AndReturn(True)
     gclient_scm.scm.SVN.RunAndGetFileList(
         options.verbose,
@@ -324,6 +339,7 @@ class SVNWrapperTestCase(BaseTestCase):
     file_info.url = self.url
     file_info.uuid = 'ABC'
     file_info.revision = 42
+    gclient_scm.gclient_utils.FindCommandExecutable('svn').AndReturn("./svn")
     gclient_scm.os.path.exists(join(self.base_path, '.git')).AndReturn(False)
     gclient_scm.os.path.exists(join(self.base_path, '.hg')).AndReturn(False)
     # Checkout.
@@ -358,6 +374,7 @@ class SVNWrapperTestCase(BaseTestCase):
     gclient_scm.os.path.exists(join(self.base_path, '.git')).AndReturn(False)
     gclient_scm.os.path.exists(join(self.base_path, '.hg')).AndReturn(False)
     gclient_scm.os.path.exists(self.base_path).AndReturn(True)
+    gclient_scm.gclient_utils.FindCommandExecutable('svn').AndReturn("./svn")
 
     # Checkout or update.
     dotted_path = join(self.base_path, '.')
@@ -398,6 +415,7 @@ class SVNWrapperTestCase(BaseTestCase):
       'UUID': 'ABC',
       'Revision': 42,
     }
+    gclient_scm.gclient_utils.FindCommandExecutable('svn').AndReturn("./svn")
     gclient_scm.os.path.exists(join(self.base_path, '.git')).AndReturn(False)
     gclient_scm.os.path.exists(join(self.base_path, '.hg')).AndReturn(False)
     gclient_scm.os.path.exists(self.base_path).AndReturn(True)
@@ -431,6 +449,7 @@ class SVNWrapperTestCase(BaseTestCase):
       'UUID': 'ABC',
       'Revision': 42,
     }
+    gclient_scm.gclient_utils.FindCommandExecutable('svn').AndReturn("./svn")
     gclient_scm.os.path.exists(join(self.base_path, '.git')).AndReturn(False)
     gclient_scm.os.path.exists(join(self.base_path, '.hg')).AndReturn(False)
     gclient_scm.os.path.exists(self.base_path).AndReturn(True)
@@ -476,6 +495,7 @@ class SVNWrapperTestCase(BaseTestCase):
         ).AndReturn('svn, version 1.5.1 (r32289)')
     gclient_scm.os.path.exists(join(self.base_path, '.svn')).AndReturn(False)
     gclient_scm.os.path.exists(join(self.base_path, 'DEPS')).AndReturn(False)
+    gclient_scm.gclient_utils.FindCommandExecutable('svn').AndReturn("./svn")
 
     # Verify no locked files.
     dotted_path = join(self.base_path, '.')
@@ -515,6 +535,7 @@ class SVNWrapperTestCase(BaseTestCase):
     gclient_scm.scm.SVN.Capture(['--version'], None
         ).AndReturn('svn, version 1.4.4 (r25188)')
     gclient_scm.os.path.exists(self.base_path).AndReturn(True)
+    gclient_scm.gclient_utils.FindCommandExecutable('svn').AndReturn("./svn")
 
     # When checking out a single file with svn 1.4, we use svn export
     files_list = self.mox.CreateMockAnything()
@@ -543,6 +564,7 @@ class SVNWrapperTestCase(BaseTestCase):
     # the old DEPS file.
     gclient_scm.os.path.exists(join(self.base_path, 'DEPS')).AndReturn(True)
     gclient_scm.os.remove(join(self.base_path, 'DEPS'))
+    gclient_scm.gclient_utils.FindCommandExecutable('svn').AndReturn("./svn")
 
     # Verify no locked files.
     gclient_scm.scm.SVN.CaptureStatus(
@@ -587,6 +609,7 @@ class SVNWrapperTestCase(BaseTestCase):
     gclient_scm.scm.SVN.Capture(['--version'], None
         ).AndReturn('svn, version 1.5.1 (r32289)')
     gclient_scm.os.path.exists(join(self.base_path, '.svn')).AndReturn(True)
+    gclient_scm.gclient_utils.FindCommandExecutable('svn').AndReturn("./svn")
 
     # Verify no locked files.
     gclient_scm.scm.SVN.CaptureStatus(None, join(self.base_path, '.')
@@ -610,6 +633,7 @@ class SVNWrapperTestCase(BaseTestCase):
 
   def testUpdateGit(self):
     options = self.Options(verbose=True)
+    gclient_scm.gclient_utils.FindCommandExecutable('svn').AndReturn("./svn")
     file_path = gclient_scm.os.path.join(self.root_dir, self.relpath, '.git')
     gclient_scm.os.path.exists(file_path).AndReturn(True)
 
@@ -623,6 +647,7 @@ class SVNWrapperTestCase(BaseTestCase):
 
   def testUpdateHg(self):
     options = self.Options(verbose=True)
+    gclient_scm.gclient_utils.FindCommandExecutable('svn').AndReturn("./svn")
     gclient_scm.os.path.exists(join(self.base_path, '.git')).AndReturn(False)
     gclient_scm.os.path.exists(join(self.base_path, '.hg')).AndReturn(True)
 
@@ -645,6 +670,7 @@ class SVNWrapperTestCase(BaseTestCase):
         ).AndReturn(True)
     gclient_scm.scm.SVN.IsValidRevision(url='%s@%s' % (self.url, 'fake')
         ).AndReturn(False)
+    gclient_scm.gclient_utils.FindCommandExecutable('svn').AndReturn("./svn")
 
     self.mox.ReplayAll()
 
@@ -1104,6 +1130,7 @@ class ManagedGitWrapperTestCaseMox(BaseTestCase):
         ).AndReturn(False)
 
     gclient_scm.scm.os.path.isdir(self.base_path).AndReturn(True)
+    gclient_scm.gclient_utils.FindCommandExecutable('git').AndReturn("./git")
 
     self.mox.ReplayAll()
 
@@ -1157,6 +1184,7 @@ class ManagedGitWrapperTestCaseMox(BaseTestCase):
 
     gclient_scm.os.path.isdir(self.base_path).AndReturn(False)
     gclient_scm.os.path.isdir(self.base_path).MultipleTimes().AndReturn(True)
+    gclient_scm.gclient_utils.FindCommandExecutable('git').AndReturn("./git")
 
     self.mox.ReplayAll()
 
diff --git a/tests/gclient_utils_test.py b/tests/gclient_utils_test.py
index 9f01c5d1e..071fd820b 100755
--- a/tests/gclient_utils_test.py
+++ b/tests/gclient_utils_test.py
@@ -30,10 +30,10 @@ class GclientUtilsUnittest(GclientUtilBase):
     members = [
         'Annotated', 'AutoFlush', 'CheckCallAndFilter',
         'CheckCallAndFilterAndHeader', 'Error', 'ExecutionQueue', 'FileRead',
-        'FileWrite', 'FindFileUpwards', 'FindGclientRoot',
-        'GetGClientRootAndEntries', 'GetEditor', 'IsDateRevision',
-        'MakeDateRevision', 'MakeFileAutoFlush', 'MakeFileAnnotated',
-        'PathDifference', 'ParseCodereviewSettingsContent',
+        'FileWrite', 'FindCommandExecutable', 'FindFileUpwards',
+        'FindGclientRoot', 'GetGClientRootAndEntries', 'GetEditor',
+        'IsDateRevision', 'MakeDateRevision', 'MakeFileAutoFlush',
+        'MakeFileAnnotated', 'PathDifference', 'ParseCodereviewSettingsContent',
         'PrintableObject', 'RemoveDirectory', 'RunEditor',
         'SplitUrlRevision', 'SyntaxErrorToError',
         'UpgradeToHttps', 'Wrapper', 'WorkItem',