diff --git a/src/Base/Tools.cpp b/src/Base/Tools.cpp
index 8957f0c126..edbf8416d0 100644
--- a/src/Base/Tools.cpp
+++ b/src/Base/Tools.cpp
@@ -153,12 +153,17 @@ std::string Base::Tools::escapedUnicodeFromUtf8(const char *s)
         return escapedstr;
 
     PyObject* escaped = PyUnicode_AsUnicodeEscapeString(unicode);
+
     if (escaped) {
+#if PY_MAJOR_VERSION >= 3
+        escapedstr = std::string(PyBytes_AsString(escaped));
+#else
         escapedstr = std::string(PyString_AsString(escaped));
+#endif
         Py_DECREF(escaped);
     }
-
     Py_DECREF(unicode);
+
     return escapedstr;
 }
 
@@ -170,7 +175,11 @@ std::string Base::Tools::escapedUnicodeToUtf8(const std::string& s)
     PyObject* unicode = PyUnicode_DecodeUnicodeEscape(s.c_str(), s.size(), "strict");
     if (!unicode)
         return string;
-
+#if PY_MAJOR_VERSION >= 3
+    if (PyUnicode_Check(unicode)) {
+        string = PyUnicode_AsUTF8(unicode);
+    }
+#else
     if (PyUnicode_Check(unicode)) {
         PyObject* value = PyUnicode_AsUTF8String(unicode);
         string = PyString_AsString(value);
@@ -179,7 +188,7 @@ std::string Base::Tools::escapedUnicodeToUtf8(const std::string& s)
     else if (PyString_Check(unicode)) {
         string = PyString_AsString(unicode);
     }
-
+#endif
     Py_DECREF(unicode);
     return string;
 }
diff --git a/src/Base/UnitPyImp.cpp b/src/Base/UnitPyImp.cpp
index cdedd53c1f..33370d6b9d 100644
--- a/src/Base/UnitPyImp.cpp
+++ b/src/Base/UnitPyImp.cpp
@@ -194,11 +194,13 @@ int UnitPy::setCustomAttributes(const char* /*attr*/, PyObject* /*obj*/)
     return 0; 
 }
 
+#if PY_MAJOR_VERSION < 3
 PyObject * UnitPy::number_divide_handler (PyObject* /*self*/, PyObject* /*other*/)
 {
     PyErr_SetString(PyExc_NotImplementedError, "Not implemented");
     return 0;
 }
+#endif
 
 PyObject * UnitPy::number_remainder_handler (PyObject* /*self*/, PyObject* /*other*/)
 {
@@ -277,10 +279,12 @@ PyObject * UnitPy::number_or_handler (PyObject* /*self*/, PyObject* /*other*/)
     return 0;
 }
 
+#if PY_MAJOR_VERSION < 3
 int UnitPy::number_coerce_handler (PyObject** /*self*/, PyObject** /*other*/)
 {
     return 1;
 }
+#endif
 
 PyObject * UnitPy::number_int_handler (PyObject* /*self*/)
 {
@@ -288,11 +292,13 @@ PyObject * UnitPy::number_int_handler (PyObject* /*self*/)
     return 0;
 }
 
+#if PY_MAJOR_VERSION < 3
 PyObject * UnitPy::number_long_handler (PyObject* /*self*/)
 {
     PyErr_SetString(PyExc_NotImplementedError, "Not implemented");
     return 0;
 }
+#endif
 
 PyObject * UnitPy::number_float_handler (PyObject* /*self*/)
 {
@@ -300,6 +306,7 @@ PyObject * UnitPy::number_float_handler (PyObject* /*self*/)
     return 0;
 }
 
+#if PY_MAJOR_VERSION < 3
 PyObject * UnitPy::number_oct_handler (PyObject* /*self*/)
 {
     PyErr_SetString(PyExc_NotImplementedError, "Not implemented");
@@ -311,3 +318,4 @@ PyObject * UnitPy::number_hex_handler (PyObject* /*self*/)
     PyErr_SetString(PyExc_NotImplementedError, "Not implemented");
     return 0;
 }
+#endif
diff --git a/src/Base/UnitsApi.cpp b/src/Base/UnitsApi.cpp
index cb7c83bfb4..3e4cd3f7c9 100644
--- a/src/Base/UnitsApi.cpp
+++ b/src/Base/UnitsApi.cpp
@@ -142,9 +142,14 @@ QString UnitsApi::schemaTranslate(const Base::Quantity& quant, double &factor, Q
 
 double UnitsApi::toDbl(PyObject *ArgObj, const Base::Unit &u)
 {
+#if PY_MAJOR_VERSION >= 3
+    if (PyUnicode_Check(ArgObj)) {
+        QString str = QString::fromUtf8(PyUnicode_AsUTF8(ArgObj));
+#else
     if (PyString_Check(ArgObj)) {
-        // Parse the string
         QString str = QString::fromLatin1(PyString_AsString(ArgObj));
+#endif
+        // Parse the string
         Quantity q = Quantity::parse(str);
         if (q.getUnit() == u)
             return q.getValue();
@@ -153,8 +158,13 @@ double UnitsApi::toDbl(PyObject *ArgObj, const Base::Unit &u)
     else if (PyFloat_Check(ArgObj)) {
         return PyFloat_AsDouble(ArgObj);
     }
+#if PY_MAJOR_VERSION < 3
     else if (PyInt_Check(ArgObj)) {
         return static_cast<double>(PyInt_AsLong(ArgObj));
+#else
+    else if (PyLong_Check(ArgObj)) {
+        return static_cast<double>(PyLong_AsLong(ArgObj));
+#endif
     }
     else {
         throw Base::UnitsMismatchError("Wrong parameter type!");
@@ -164,17 +174,27 @@ double UnitsApi::toDbl(PyObject *ArgObj, const Base::Unit &u)
 Quantity UnitsApi::toQuantity(PyObject *ArgObj, const Base::Unit &u)
 {
     double d;
+#if PY_MAJOR_VERSION >= 3
+    if (PyUnicode_Check(ArgObj)) {
+        QString str = QString::fromUtf8(PyUnicode_AsUTF8(ArgObj));
+#else
     if (PyString_Check(ArgObj)) {
-        // Parse the string
         QString str = QString::fromLatin1(PyString_AsString(ArgObj));
+#endif
+        // Parse the string
         Quantity q = Quantity::parse(str);
         d = q.getValue();
     }
     else if (PyFloat_Check(ArgObj)) {
         d = PyFloat_AsDouble(ArgObj);
     }
+#if PY_MAJOR_VERSION < 3
     else if (PyInt_Check(ArgObj)) {
         d = static_cast<double>(PyInt_AsLong(ArgObj));
+#else
+    else if (PyLong_Check(ArgObj)) {
+        d = static_cast<double>(PyLong_AsLong(ArgObj));
+#endif
     }
     else {
         throw Base::UnitsMismatchError("Wrong parameter type!");
diff --git a/src/Base/VectorPyImp.cpp b/src/Base/VectorPyImp.cpp
index 0b9bcc34ef..b1b3bf4f2b 100644
--- a/src/Base/VectorPyImp.cpp
+++ b/src/Base/VectorPyImp.cpp
@@ -131,8 +131,14 @@ PyObject* VectorPy::number_multiply_handler(PyObject *self, PyObject *other)
             double b = PyFloat_AsDouble(other);
             return new VectorPy(a * b);
         }
-        else if (PyInt_Check(other)) {
-            long b = PyInt_AsLong(other);
+#if PY_MAJOR_VERSION < 3
+    else if (PyInt_Check(other)) {
+        Base::Vector3d a = static_cast<VectorPy*>(self) ->value();
+        long b = PyInt_AsLong(other);
+#else
+    else if (PyLong_Check(other)) {
+        long b = PyLong_AsLong(other);
+#endif
             return new VectorPy(a * (double)b);
         }
         else {
@@ -146,8 +152,13 @@ PyObject* VectorPy::number_multiply_handler(PyObject *self, PyObject *other)
             double b = PyFloat_AsDouble(self);
             return new VectorPy(a * b);
         }
+#if PY_MAJOR_VERSION >= 3
+        else if (PyLong_Check(self)) {
+            long b = PyLong_AsLong(self);
+#else
         else if (PyInt_Check(self)) {
             long b = PyInt_AsLong(self);
+#endif
             return new VectorPy(a * (double)b);
         }
         else {
@@ -580,11 +591,13 @@ int VectorPy::setCustomAttributes(const char* /*attr*/, PyObject* /*obj*/)
     return 0; 
 }
 
+#if PY_MAJOR_VERSION < 3
 PyObject * VectorPy::number_divide_handler (PyObject* /*self*/, PyObject* /*other*/)
 {
     PyErr_SetString(PyExc_NotImplementedError, "Not implemented");
     return 0;
 }
+#endif
 
 PyObject * VectorPy::number_remainder_handler (PyObject* /*self*/, PyObject* /*other*/)
 {
@@ -663,10 +676,12 @@ PyObject * VectorPy::number_or_handler (PyObject* /*self*/, PyObject* /*other*/)
     return 0;
 }
 
+#if PY_MAJOR_VERSION < 3
 int VectorPy::number_coerce_handler (PyObject ** /*self*/, PyObject ** /*other*/)
 {
     return 1;
 }
+#endif
 
 PyObject * VectorPy::number_int_handler (PyObject* /*self*/)
 {
@@ -674,11 +689,13 @@ PyObject * VectorPy::number_int_handler (PyObject* /*self*/)
     return 0;
 }
 
+#if PY_MAJOR_VERSION < 3
 PyObject * VectorPy::number_long_handler (PyObject* /*self*/)
 {
     PyErr_SetString(PyExc_NotImplementedError, "Not implemented");
     return 0;
 }
+#endif
 
 PyObject * VectorPy::number_float_handler (PyObject* /*self*/)
 {
@@ -686,6 +703,7 @@ PyObject * VectorPy::number_float_handler (PyObject* /*self*/)
     return 0;
 }
 
+#if PY_MAJOR_VERSION < 3
 PyObject * VectorPy::number_oct_handler (PyObject* /*self*/)
 {
     PyErr_SetString(PyExc_NotImplementedError, "Not implemented");
@@ -697,3 +715,4 @@ PyObject * VectorPy::number_hex_handler (PyObject* /*self*/)
     PyErr_SetString(PyExc_NotImplementedError, "Not implemented");
     return 0;
 }
+#endif
diff --git a/src/Base/swigpyrun.inl b/src/Base/swigpyrun.inl
index f71e7a6e6f..0eedaaa87a 100644
--- a/src/Base/swigpyrun.inl
+++ b/src/Base/swigpyrun.inl
@@ -88,7 +88,11 @@ void cleanupSWIG_T(const char* TypeName)
         PyObject *key, *value;
         pos = 0;
         while (PyDict_Next(dict, &pos, &key, &value)) {
+#if PY_MAJOR_VERSION >= 3
+            if (value != Py_None && PyUnicode_Check(key)) {
+#else
             if (value != Py_None && PyString_Check(key)) {
+#endif
                 void* ptr = 0;
                 if (SWIG_ConvertPtr(value, &ptr, 0, 0) == 0)
                     PyDict_SetItem(dict, key, Py_None);