diff --git a/src/Base/MatrixPyImp.cpp b/src/Base/MatrixPyImp.cpp
index d7f4bf2d92..a781f9d812 100644
--- a/src/Base/MatrixPyImp.cpp
+++ b/src/Base/MatrixPyImp.cpp
@@ -481,7 +481,11 @@ PyObject* MatrixPy::analyze(PyObject * args)
 
     PY_TRY {
         std::string type = getMatrixPtr()->analyse();
+#if PY_MAJOR_VERSION < 3
         return PyString_FromString(type.c_str());
+#else
+        return PyUniCode_FromString(type.c_str());
+#endif
     }
     PY_CATCH;
 }
@@ -696,11 +700,13 @@ int MatrixPy::setCustomAttributes(const char* /*attr*/, PyObject* /*obj*/)
     return 0; 
 }
 
+#if PY_MAJOR_VERSION < 3
 PyObject * MatrixPy::number_divide_handler (PyObject* /*self*/, PyObject* /*other*/)
 {
     PyErr_SetString(PyExc_NotImplementedError, "Not implemented");
     return 0;
 }
+#endif
 
 PyObject * MatrixPy::number_remainder_handler (PyObject* /*self*/, PyObject* /*other*/)
 {
@@ -779,10 +785,12 @@ PyObject * MatrixPy::number_or_handler (PyObject* /*self*/, PyObject* /*other*/)
     return 0;
 }
 
+#if PY_MAJOR_VERSION < 3
 int MatrixPy::number_coerce_handler (PyObject ** /*self*/, PyObject ** /*other*/)
 {
     return 1;
 }
+#endif
 
 PyObject * MatrixPy::number_int_handler (PyObject * /*self*/)
 {
@@ -790,11 +798,13 @@ PyObject * MatrixPy::number_int_handler (PyObject * /*self*/)
     return 0;
 }
 
+#if PY_MAJOR_VERSION < 3
 PyObject * MatrixPy::number_long_handler (PyObject * /*self*/)
 {
     PyErr_SetString(PyExc_NotImplementedError, "Not implemented");
     return 0;
 }
+#endif
 
 PyObject * MatrixPy::number_float_handler (PyObject * /*self*/)
 {
@@ -802,6 +812,7 @@ PyObject * MatrixPy::number_float_handler (PyObject * /*self*/)
     return 0;
 }
 
+#if PY_MAJOR_VERSION < 3
 PyObject * MatrixPy::number_oct_handler (PyObject * /*self*/)
 {
     PyErr_SetString(PyExc_NotImplementedError, "Not implemented");
@@ -813,3 +824,4 @@ PyObject * MatrixPy::number_hex_handler (PyObject * /*self*/)
     PyErr_SetString(PyExc_NotImplementedError, "Not implemented");
     return 0;
 }
+#endif
diff --git a/src/Base/PyTools.c b/src/Base/PyTools.c
index 3e77359a13..65293202a8 100644
--- a/src/Base/PyTools.c
+++ b/src/Base/PyTools.c
@@ -149,7 +149,7 @@ PP_Debug_Function(PyObject *func, PyObject *args)
     /* expand tuple at front */
     // it seems that some versions of python want just 2 arguments; in that
     // case, remove trailing 1
-#if (PY_MAJOR_VERSION==2)&&(PY_MINOR_VERSION>=2)
+#if (PY_MAJOR_VERSION>=2)&&(PY_MINOR_VERSION>=2)
     oops = _PyTuple_Resize(&args, (1 + PyTuple_Size(args))); 
 #else
     oops = _PyTuple_Resize(&args, (1 + PyTuple_Size(args)),1); 
@@ -241,9 +241,15 @@ void PP_Fetch_Error_Text()
     pystring = NULL;
     if (errobj != NULL &&
        (pystring = PyObject_Str(errobj)) != NULL &&      /* str(errobj) */
+#if PY_MAJOR_VERSION >= 3
+       (PyUnicode_Check(pystring)) )                      /* str() increfs */
+    {
+        strncpy(PP_last_error_type, PyUnicode_AsUTF8(pystring), MAX); /*Py->C*/
+#else
        (PyString_Check(pystring)) )                      /* str() increfs */
     {
         strncpy(PP_last_error_type, PyString_AsString(pystring), MAX); /*Py->C*/
+#endif
         PP_last_error_type[MAX-1] = '\0';
     }
     else
@@ -264,7 +270,11 @@ void PP_Fetch_Error_Text()
         PyObject* value = PyDict_GetItemString(errdata,"swhat");
         
         if (value!=NULL) {
-            strncpy(PP_last_error_info, PyString_AsString(value), MAX);
+#if PY_MAJOR_VERSION < 3
+            strncpy(PP_last_error_info, PyString_AsString(pystring), MAX);
+#else
+            strncpy(PP_last_error_info, PyUnicode_AsUTF8(pystring), MAX);
+#endif
             PP_last_error_info[MAX-1] = '\0';
         }
 
@@ -273,9 +283,15 @@ void PP_Fetch_Error_Text()
     }
     else if (errdata != NULL &&
        (pystring = PyObject_Str(errdata)) != NULL &&     /* str(): increfs */
+#if PY_MAJOR_VERSION >= 3
+       (PyUnicode_Check(pystring)) )
+    {
+        strncpy(PP_last_error_info, PyUnicode_AsUTF8(pystring), MAX); /*Py->C*/
+#else
        (PyString_Check(pystring)) )
     {
         strncpy(PP_last_error_info, PyString_AsString(pystring), MAX); /*Py->C*/
+#endif
         PP_last_error_info[MAX-1] = '\0';
     }
     else 
@@ -289,7 +305,12 @@ void PP_Fetch_Error_Text()
 
     pystring = NULL;
     if (errtraceback != NULL &&
+#if PY_MAJOR_VERSION < 3
        (PP_Run_Function("StringIO", "StringIO", "O", &pystring, "()") == 0) &&
+#else
+       (PP_Run_Function("io", "StringIO", "O", &pystring, "()") == 0) &&
+#endif
+
        (PyTraceBack_Print(errtraceback, pystring) == 0) &&
        (PP_Run_Method(pystring, "getvalue", "s", &tempstr, "()") == 0) )
     {
@@ -581,7 +602,11 @@ PP_Run_Bytecode(PyObject *codeobj,           /* run compiled bytecode object */
     if (PP_DEBUG)
         presult = PP_Debug_Bytecode(codeobj, dict);        /* run in pdb */
     else
+#if PY_MAJOR_VERSION >= 3
+        presult = PyEval_EvalCode((PyObject*)codeobj, dict, dict);
+#else
         presult = PyEval_EvalCode((PyCodeObject *)codeobj, dict, dict);
+#endif
     return PP_Convert_Result(presult, resfmt, restarget);  /* expr val to C */
 }
 
diff --git a/src/Base/QuantityPyImp.cpp b/src/Base/QuantityPyImp.cpp
index 1eb95ea5ee..310ac007d9 100644
--- a/src/Base/QuantityPyImp.cpp
+++ b/src/Base/QuantityPyImp.cpp
@@ -221,9 +221,14 @@ PyObject * QuantityPy::number_int_handler (PyObject *self)
     }
 
     QuantityPy* q = static_cast<QuantityPy*>(self);
+#if PY_MAJOR_VERSION < 3
     return PyInt_FromLong((long)q->getValue());
+#else
+    return PyLong_FromLong((long)q->getValue());
+#endif
 }
 
+#if PY_MAJOR_VERSION < 3
 PyObject * QuantityPy::number_long_handler (PyObject *self)
 {
     if (!PyObject_TypeCheck(self, &(QuantityPy::Type))) {
@@ -234,6 +239,7 @@ PyObject * QuantityPy::number_long_handler (PyObject *self)
     QuantityPy* q = static_cast<QuantityPy*>(self);
     return PyInt_FromLong((long)q->getValue());
 }
+#endif
 
 PyObject * QuantityPy::number_negative_handler (PyObject *self)
 {
@@ -274,7 +280,7 @@ PyObject* QuantityPy::number_add_handler(PyObject *self, PyObject *other)
     if (!PyObject_TypeCheck(self, &(QuantityPy::Type)) ||
         !PyObject_TypeCheck(other, &(QuantityPy::Type))) {
         std::stringstream ret;
-        ret << self->ob_type->tp_name << " and " << other->ob_type->tp_name
+        ret << Py_TYPE(self)->tp_name << " and " << Py_TYPE(other)->tp_name
             << " cannot be mixed in Quantity.__add__.\n"
             << "Make sure to use matching types.";
         PyErr_SetString(PyExc_TypeError, ret.str().c_str());
@@ -297,7 +303,7 @@ PyObject* QuantityPy::number_subtract_handler(PyObject *self, PyObject *other)
     if (!PyObject_TypeCheck(self, &(QuantityPy::Type)) ||
         !PyObject_TypeCheck(other, &(QuantityPy::Type))) {
         std::stringstream ret;
-        ret << self->ob_type->tp_name << " and " << other->ob_type->tp_name
+        ret << Py_TYPE(self)->tp_name << " and " << Py_TYPE(other)->tp_name
             << " cannot be mixed in Quantity.__sub__.\n"
             << "Make sure to use matching types.";
         PyErr_SetString(PyExc_TypeError, ret.str().c_str());
@@ -328,9 +334,15 @@ PyObject* QuantityPy::number_multiply_handler(PyObject *self, PyObject *other)
             double b = PyFloat_AsDouble(other);
             return new QuantityPy(new Quantity(*a*b) );
         }
+#if PY_MAJOR_VERSION < 3
         else if (PyInt_Check(other)) {
             Base::Quantity *a = static_cast<QuantityPy*>(self) ->getQuantityPtr();
             double b = (double)PyInt_AsLong(other);
+#else
+        else if (PyLong_Check(other)) {
+            Base::Quantity *a = static_cast<QuantityPy*>(self) ->getQuantityPtr();
+            double b = (double)PyLong_AsLong(other);
+#endif
             return new QuantityPy(new Quantity(*a*b) );
         }
     }
@@ -340,9 +352,15 @@ PyObject* QuantityPy::number_multiply_handler(PyObject *self, PyObject *other)
             double b = PyFloat_AsDouble(self);
             return new QuantityPy(new Quantity(*a*b) );
         }
+#if PY_MAJOR_VERSION < 3
         else if (PyInt_Check(self)) {
             Base::Quantity *a = static_cast<QuantityPy*>(other) ->getQuantityPtr();
             double b = (double)PyInt_AsLong(self);
+#else
+        else if (PyLong_Check(self)) {
+            Base::Quantity *a = static_cast<QuantityPy*>(other) ->getQuantityPtr();
+            double b = (double)PyLong_AsLong(self);
+#endif
             return new QuantityPy(new Quantity(*a*b) );
         }
     }
@@ -351,6 +369,7 @@ PyObject* QuantityPy::number_multiply_handler(PyObject *self, PyObject *other)
     return 0;
 }
 
+#if PY_MAJOR_VERSION < 3
 PyObject * QuantityPy::number_divide_handler (PyObject *self, PyObject *other)
 {
     if (!PyObject_TypeCheck(self, &(QuantityPy::Type))) {
@@ -379,6 +398,7 @@ PyObject * QuantityPy::number_divide_handler (PyObject *self, PyObject *other)
         return 0;
     }
 }
+#endif
 
 PyObject * QuantityPy::number_remainder_handler (PyObject *self, PyObject *other)
 {
@@ -398,8 +418,13 @@ PyObject * QuantityPy::number_remainder_handler (PyObject *self, PyObject *other
     else if (PyFloat_Check(other)) {
         d2 = PyFloat_AsDouble(other);
     }
+#if PY_MAJOR_VERSION < 3
     else if (PyInt_Check(other)) {
         d2 = (double)PyInt_AsLong(other);
+#else
+    else if (PyLong_Check(other)) {
+        d2 = (double)PyLong_AsLong(other);
+#endif
     }
     else {
         PyErr_SetString(PyExc_TypeError, "Expected quantity or number");
@@ -443,9 +468,15 @@ PyObject * QuantityPy::number_power_handler (PyObject *self, PyObject *other, Py
         double b = PyFloat_AsDouble(other);
         return new QuantityPy(new Quantity(a->pow(b)) );
     }
+#if PY_MAJOR_VERSION < 3
     else if (PyInt_Check(other)) {
         Base::Quantity *a = static_cast<QuantityPy*>(self) ->getQuantityPtr();
         double b = (double)PyInt_AsLong(other);
+#else
+    else if (PyLong_Check(other)) {
+        Base::Quantity *a = static_cast<QuantityPy*>(self) ->getQuantityPtr();
+        double b = (double)PyLong_AsLong(other);
+#endif
         return new QuantityPy(new Quantity(a->pow(b)));
     }
     else {
@@ -621,6 +652,7 @@ PyObject * QuantityPy::number_or_handler (PyObject* /*self*/, PyObject* /*other*
     return 0;
 }
 
+#if PY_MAJOR_VERSION < 3
 int QuantityPy::number_coerce_handler (PyObject** /*self*/, PyObject** /*other*/)
 {
     return 1;
@@ -637,3 +669,4 @@ PyObject * QuantityPy::number_hex_handler (PyObject* /*self*/)
     PyErr_SetString(PyExc_TypeError, "hex() argument can't be converted to hex");
     return 0;
 }
+#endif