diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 428a37f..731bbc9 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -23,11 +23,17 @@ v1.2.9 (unreleased)
 
 Bug fix release
 
+Fix
+---
+
+- Fix #20: Set the :func:`warnings.warn` stacklevel to 2 if the Python implementation is `PyPy <https://www.pypy.org/>`_.
+
 Other
 -----
 
 - Change the Tox configuration to run tests on PyPy v2.7 and 3.6.
 
+
 v1.2.8 (2020-04-05)
 ===================
 
@@ -55,7 +61,6 @@ Documentation
 
 - Add a detailed documentation about :ref:`sphinx_deco`.
 
-
 Other
 -----
 
diff --git a/deprecated/classic.py b/deprecated/classic.py
index bbdce5a..f3f67d6 100644
--- a/deprecated/classic.py
+++ b/deprecated/classic.py
@@ -10,18 +10,24 @@
 import functools
 import inspect
 import warnings
+import platform
 
 import wrapt
 
 try:
-    # If the c extension for wrapt was compiled and wrapt/_wrappers.pyd exists, then the
+    # If the C extension for wrapt was compiled and wrapt/_wrappers.pyd exists, then the
     # stack level that should be passed to warnings.warn should be 2. However, if using
     # a pure python wrapt, a extra stacklevel is required.
     import wrapt._wrappers
 
-    _stacklevel = 2
+    _routine_stacklevel = 2
+    _class_stacklevel = 2
 except ImportError:
-    _stacklevel = 3
+    _routine_stacklevel = 3
+    if platform.python_implementation() == "PyPy":
+        _class_stacklevel = 2
+    else:
+        _class_stacklevel = 3
 
 string_types = (type(b''), type(u''))
 
@@ -158,13 +164,13 @@ def wrapped_cls(cls, *args, **kwargs):
                 with warnings.catch_warnings():
                     if self.action:
                         warnings.simplefilter(self.action, self.category)
-                    warnings.warn(msg, category=self.category, stacklevel=_stacklevel)
+                    warnings.warn(msg, category=self.category, stacklevel=_class_stacklevel)
                 if old_new1 is object.__new__:
                     return old_new1(cls)
                 # actually, we don't know the real signature of *old_new1*
-                return old_new1(*args, **kwargs)
+                return old_new1(cls, *args, **kwargs)
 
-            wrapped.__new__ = classmethod(wrapped_cls)
+            wrapped.__new__ = staticmethod(wrapped_cls)
 
         return wrapped
 
@@ -271,7 +277,7 @@ def wrapper_function(wrapped_, instance_, args_, kwargs_):
                 with warnings.catch_warnings():
                     if action:
                         warnings.simplefilter(action, category)
-                    warnings.warn(msg, category=category, stacklevel=_stacklevel)
+                    warnings.warn(msg, category=category, stacklevel=_routine_stacklevel)
                 return wrapped_(*args_, **kwargs_)
 
             return wrapper_function(wrapped)