diff --git a/CHANGES b/CHANGES
index ed9eb14..b64b782 100644
--- a/CHANGES
+++ b/CHANGES
@@ -13,6 +13,8 @@ Modules/
 Lib/
 * ldap.__version__, ldap.__author__ and ldap.__license__ now
   imported from new sub-module ldap.pkginfo also to setup.py
+* Added safety assertion when importing _ldap:
+  ldap.pkginfo.__version__ must match _ldap.__version__
 * removed stand-alone module dsml
 * slapdtest.SlapdObject.restart() just restarts slapd
   without cleaning any data
diff --git a/Lib/ldap/__init__.py b/Lib/ldap/__init__.py
index e679de5..c1c5ef1 100644
--- a/Lib/ldap/__init__.py
+++ b/Lib/ldap/__init__.py
@@ -17,7 +17,11 @@
   _trace_file = sys.stderr
   _trace_stack_limit = None
 
+from ldap.pkginfo import __version__
+
 import _ldap
+assert _ldap.__version__==__version__, \
+       ImportError('ldap %s and _ldap %s version mismatch!' % (__version__,_ldap.__version__))
 from _ldap import *
 
 OPT_NAMES_DICT = {}
diff --git a/Lib/ldap/controls/__init__.py b/Lib/ldap/controls/__init__.py
index d504d49..56d611b 100644
--- a/Lib/ldap/controls/__init__.py
+++ b/Lib/ldap/controls/__init__.py
@@ -9,7 +9,19 @@
 Each class provides support for a certain control.
 """
 
-from ldap import __version__
+from ldap.pkginfo import __version__
+
+import _ldap
+assert _ldap.__version__==__version__, \
+       ImportError('ldap %s and _ldap %s version mismatch!' % (__version__,_ldap.__version__))
+
+import ldap
+
+try:
+  from pyasn1.error import PyAsn1Error
+except ImportError:
+  PyAsn1Error = None
+
 
 __all__ = [
   'KNOWN_RESPONSE_CONTROLS',
@@ -32,13 +44,6 @@
 # response control OID to class registry
 KNOWN_RESPONSE_CONTROLS = {}
 
-import _ldap,ldap
-
-try:
-  from pyasn1.error import PyAsn1Error
-except ImportError:
-  PyAsn1Error = None
-
 
 class RequestControl:
   """
diff --git a/Lib/ldap/controls/libldap.py b/Lib/ldap/controls/libldap.py
index 53a02a4..f6ea42c 100644
--- a/Lib/ldap/controls/libldap.py
+++ b/Lib/ldap/controls/libldap.py
@@ -6,7 +6,14 @@
 See https://www.python-ldap.org/ for details.
 """
 
-import _ldap,ldap
+from ldap.pkginfo import __version__
+
+import _ldap
+assert _ldap.__version__==__version__, \
+       ImportError('ldap %s and _ldap %s version mismatch!' % (__version__,_ldap.__version__))
+
+import ldap
+
 from ldap.controls import RequestControl,LDAPControl,KNOWN_RESPONSE_CONTROLS
 
 
diff --git a/Lib/ldap/dn.py b/Lib/ldap/dn.py
index 75465ed..daab8ab 100644
--- a/Lib/ldap/dn.py
+++ b/Lib/ldap/dn.py
@@ -7,10 +7,11 @@
 - Tested with Python 2.0+
 """
 
-from ldap import __version__
-
+from ldap.pkginfo import __version__
 
 import _ldap
+assert _ldap.__version__==__version__, \
+       ImportError('ldap %s and _ldap %s version mismatch!' % (__version__,_ldap.__version__))
 
 import ldap.functions