diff --git a/requests/__init__.py b/requests/__init__.py
index 90a0d11a17..d4461ec94b 100644
--- a/requests/__init__.py
+++ b/requests/__init__.py
@@ -40,44 +40,34 @@
 :license: Apache 2.0, see LICENSE for more details.
 """
 
+# Check urllib3 for compatibility.
 import urllib3
-import chardet
-import warnings
-from .exceptions import RequestsDependencyWarning
-
-
-def check_compatibility(urllib3_version, chardet_version):
-    urllib3_version = urllib3_version.split('.')
-    assert urllib3_version != ['dev']  # Verify urllib3 isn't installed from git.
-
-    # Sometimes, urllib3 only reports its version as 16.1.
-    if len(urllib3_version) == 2:
-        urllib3_version.append('0')
-
-    # Check urllib3 for compatibility.
-    major, minor, patch = urllib3_version  # noqa: F811
-    major, minor, patch = int(major), int(minor), int(patch)
-    # urllib3 >= 1.21.1, < 1.22
+urllib3_version = urllib3.__version__.split('.')
+# Sometimes, urllib3 only reports its version as 16.1.
+if len(urllib3_version) == 2:
+    urllib3_version.append('0')
+major, minor, patch = urllib3_version
+major, minor, patch = int(major), int(minor), int(patch)
+# urllib3 >= 1.21.1, < 1.22
+try:
     assert major == 1
     assert minor >= 21
     assert minor <= 22
+except AssertionError:
+    raise RuntimeError('Requests dependency \'urllib3\' must be version >= 1.21.1, < 1.22!')
+
 
-    # Check chardet for compatibility.
-    major, minor, patch = chardet_version.split('.')[:3]
-    major, minor, patch = int(major), int(minor), int(patch)
-    # chardet >= 3.0.2, < 3.1.0
+# Check chardet for compatibility.
+import chardet
+major, minor, patch = chardet.__version__.split('.')[:3]
+major, minor, patch = int(major), int(minor), int(patch)
+# chardet >= 3.0.2, < 3.1.0
+try:
     assert major == 3
     assert minor < 1
     assert patch >= 2
-
-
-# Check imported dependencies for compatibility.
-try:
-    check_compatibility(urllib3.__version__, chardet.__version__)
-except (AssertionError, ValueError):
-    warnings.warn("urllib3 ({0}) or chardet ({1}) doesn't match a supported "
-                  "version!".format(urllib3.__version__, chardet.__version__),
-                  RequestsDependencyWarning)
+except AssertionError:
+    raise RuntimeError('Requests dependency \'chardet\' must be version >= 3.0.2, < 3.1.0!')
 
 # Attempt to enable urllib3's SNI support, if possible
 try:
@@ -86,6 +76,8 @@ def check_compatibility(urllib3_version, chardet_version):
 except ImportError:
     pass
 
+import warnings
+
 # urllib3's DependencyWarnings should be silenced.
 from urllib3.exceptions import DependencyWarning
 warnings.simplefilter('ignore', DependencyWarning)
diff --git a/requests/exceptions.py b/requests/exceptions.py
index be7eaed6b9..da5af10bfd 100644
--- a/requests/exceptions.py
+++ b/requests/exceptions.py
@@ -115,8 +115,3 @@ class RequestsWarning(Warning):
 class FileModeWarning(RequestsWarning, DeprecationWarning):
     """A file was opened in text mode, but Requests determined its binary length."""
     pass
-
-
-class RequestsDependencyWarning(RequestsWarning):
-    """An imported dependency doesn't match the expected version range."""
-    pass