diff --git a/rostests/apitests/gdi32/CMakeLists.txt b/rostests/apitests/gdi32/CMakeLists.txt
index e4ad41a40f7..f8147de469a 100644
--- a/rostests/apitests/gdi32/CMakeLists.txt
+++ b/rostests/apitests/gdi32/CMakeLists.txt
@@ -6,6 +6,7 @@ list(APPEND SOURCE
     AddFontResource.c
     AddFontResourceEx.c
     BeginPath.c
+    CombineRgn.c
     CombineTransform.c
     CreateBitmap.c
     CreateBitmapIndirect.c
diff --git a/rostests/apitests/gdi32/CombineRgn.c b/rostests/apitests/gdi32/CombineRgn.c
new file mode 100644
index 00000000000..65b1ce779d3
--- /dev/null
+++ b/rostests/apitests/gdi32/CombineRgn.c
@@ -0,0 +1,198 @@
+/*
+ * PROJECT:         ReactOS api tests
+ * LICENSE:         GPL - See COPYING in the top level directory
+ * PURPOSE:         Test for ...
+ * PROGRAMMERS:     Timo Kreuzer
+ */
+
+#include <stdio.h>
+#include <wine/test.h>
+#include <windows.h>
+
+#define ok_long(expression, result) \
+    { \
+        int _value = (expression); \
+        ok(_value == (result), "Wrong value for %s, expected " #result " (0x%x), got 0x%x\n", \
+           #expression, (int)(result), _value); \
+    }
+
+
+void Test_CombineRgn_COPY()
+{
+    HRGN hrgn1, hrgn2, hrgn3;
+
+    hrgn1 = CreateRectRgn(0, 0, 0, 0);
+    hrgn2 = CreateRectRgn(0, 0, 10, 10);
+    hrgn3 = CreateRectRgn(5, 5, 20, 20);
+
+    SetLastError(0xbadbabe);
+    ok_long(CombineRgn(NULL, NULL, NULL, RGN_COPY), ERROR);
+    ok_long(CombineRgn(NULL, hrgn1, NULL, RGN_COPY), ERROR);
+    ok_long(CombineRgn(NULL, NULL, hrgn1, RGN_COPY), ERROR);
+    ok_long(CombineRgn(NULL, hrgn1, hrgn2, RGN_COPY), ERROR);
+    ok_long(GetLastError(), 0xbadbabe);
+
+    ok_long(CombineRgn(hrgn1, hrgn2, hrgn3, RGN_COPY), SIMPLEREGION);
+    ok(EqualRgn(hrgn1, hrgn2), "Region is not correct\n");
+
+    ok_long(CombineRgn(hrgn1, hrgn1, NULL, RGN_COPY), SIMPLEREGION);
+    ok(EqualRgn(hrgn1, hrgn2), "Region is not correct\n");
+
+    ok_long(CombineRgn(hrgn1, hrgn3, GetStockObject(BLACK_PEN), RGN_COPY), SIMPLEREGION);
+    ok(EqualRgn(hrgn1, hrgn3), "Region is not correct\n");
+
+    ok_long(CombineRgn(hrgn1, GetStockObject(BLACK_PEN), hrgn2, RGN_COPY), ERROR);
+    ok(EqualRgn(hrgn1, hrgn3), "Region is not correct\n");
+
+    ok_long(CombineRgn(hrgn1, NULL, hrgn2, RGN_COPY), ERROR);
+    ok(EqualRgn(hrgn1, hrgn3), "Region is not correct\n");
+
+    ok_long(CombineRgn(hrgn1, NULL, NULL, RGN_COPY), ERROR);
+    ok(EqualRgn(hrgn1, hrgn3), "Region is not correct\n");
+
+    ok_long(GetLastError(), 0xbadbabe);
+
+}
+
+void Test_CombineRgn_AND()
+{
+    HRGN hrgn1, hrgn2, hrgn3;
+
+    hrgn1 = CreateRectRgn(0, 0, 0, 0);
+    hrgn2 = CreateRectRgn(0, 0, 10, 10);
+    hrgn3 = CreateRectRgn(5, 5, 20, 20);
+
+    SetLastError(0xbadbabe);
+    ok_long(CombineRgn(NULL, NULL, NULL, RGN_AND), ERROR);
+    ok_long(CombineRgn(hrgn1, NULL, NULL, RGN_AND), ERROR);
+    ok_long(CombineRgn(hrgn1, hrgn2, NULL, RGN_AND), ERROR);
+    ok_long(CombineRgn(hrgn1, NULL, hrgn2, RGN_AND), ERROR);
+    ok_long(CombineRgn(hrgn1, GetStockObject(BLACK_PEN), hrgn2, RGN_AND), ERROR);
+    ok_long(CombineRgn(hrgn1, hrgn2, GetStockObject(BLACK_PEN), RGN_AND), ERROR);
+    ok_long(GetLastError(), 0xbadbabe);
+
+
+    ok_long(CombineRgn(hrgn1, hrgn2, hrgn3, RGN_AND), SIMPLEREGION);
+    SetRectRgn(hrgn2, 5, 5, 10, 10);
+    ok(EqualRgn(hrgn1, hrgn2), "Region is not correct\n");
+
+    SetRectRgn(hrgn2, 0, 0, 5, 5);
+    SetRectRgn(hrgn3, 5, 0, 10, 5);
+    ok_long(CombineRgn(hrgn1, hrgn2, hrgn3, RGN_AND), NULLREGION);
+    SetRectRgn(hrgn2, 0, 0, 0, 0);
+    ok(EqualRgn(hrgn1, hrgn2), "Region is not correct\n");
+
+    SetRectRgn(hrgn2, 0, 0, 20, 20);
+    SetRectRgn(hrgn3, 5, 5, 10, 10);
+    ok_long(CombineRgn(hrgn1, hrgn2, hrgn3, RGN_AND), SIMPLEREGION);
+    SetRectRgn(hrgn2, 5, 5, 10, 10);
+    ok(EqualRgn(hrgn1, hrgn2), "Region is not correct\n");
+
+
+    SetRectRgn(hrgn2, 0, 0, 30, 10);
+    SetRectRgn(hrgn3, 10, 10, 20, 30);
+    ok_long(CombineRgn(hrgn1, hrgn2, hrgn3, RGN_OR), COMPLEXREGION);
+    SetRectRgn(hrgn2, 10, 0, 30, 30);
+    ok_long(CombineRgn(hrgn1, hrgn1, hrgn2, RGN_AND), COMPLEXREGION);
+    ok_long(CombineRgn(hrgn1, hrgn1, hrgn1, RGN_AND), COMPLEXREGION);
+    SetRectRgn(hrgn2, 10, 10, 30, 30);
+    ok_long(CombineRgn(hrgn1, hrgn1, hrgn2, RGN_AND), SIMPLEREGION);
+    SetRectRgn(hrgn2, 0, 0, 10, 10);
+    ok_long(CombineRgn(hrgn1, hrgn1, hrgn2, RGN_AND), NULLREGION);
+
+    SetRectRgn(hrgn1, 0, 0, 30, 10);
+    ok_long(CombineRgn(hrgn1, hrgn1, hrgn1, RGN_AND), SIMPLEREGION);
+
+}
+
+void Test_CombineRgn_OR()
+{
+    HRGN hrgn1, hrgn2, hrgn3;
+
+    hrgn1 = CreateRectRgn(0, 0, 0, 0);
+    hrgn2 = CreateRectRgn(0, 0, 5, 5);
+    hrgn3 = CreateRectRgn(5, 0, 10, 5);
+    ok_long(CombineRgn(hrgn1, hrgn2, hrgn3, RGN_OR), SIMPLEREGION);
+    SetRectRgn(hrgn2, 0, 0, 10, 5);
+    ok(EqualRgn(hrgn1, hrgn2), "Region is not correct\n");
+
+    SetRectRgn(hrgn2, 0, 0, 10, 10);
+    SetRectRgn(hrgn3, 10, 10, 20, 20);
+    ok_long(CombineRgn(hrgn1, hrgn2, hrgn3, RGN_OR), COMPLEXREGION);
+    SetRectRgn(hrgn2, 10, 0, 20, 10);
+    ok_long(CombineRgn(hrgn1, hrgn1, hrgn2, RGN_OR), COMPLEXREGION);
+    ok_long(CombineRgn(hrgn1, hrgn1, hrgn1, RGN_OR), COMPLEXREGION);
+    SetRectRgn(hrgn2, 0, 10, 10, 20);
+    ok_long(CombineRgn(hrgn1, hrgn1, hrgn2, RGN_OR), SIMPLEREGION);
+    SetRectRgn(hrgn2, 0, 0, 20, 20);
+    ok(EqualRgn(hrgn1, hrgn2), "Region is not correct\n");
+
+}
+
+void Test_CombineRgn_DIFF()
+{
+    HRGN hrgn1, hrgn2, hrgn3;
+
+    hrgn1 = CreateRectRgn(0, 0, 0, 0);
+    hrgn2 = CreateRectRgn(0, 0, 10, 10);
+    hrgn3 = CreateRectRgn(5, 0, 10, 5);
+
+    SetLastError(0xbadbabe);
+    ok_long(CombineRgn(NULL, NULL, NULL, RGN_DIFF), ERROR);
+    ok_long(CombineRgn(hrgn1, NULL, NULL, RGN_DIFF), ERROR);
+    ok_long(CombineRgn(hrgn1, hrgn2, NULL, RGN_DIFF), ERROR);
+    ok_long(CombineRgn(hrgn1, NULL, hrgn2, RGN_DIFF), ERROR);
+    ok_long(CombineRgn(hrgn1, GetStockObject(BLACK_PEN), hrgn2, RGN_DIFF), ERROR);
+    ok_long(CombineRgn(hrgn1, hrgn2, GetStockObject(BLACK_PEN), RGN_DIFF), ERROR);
+    ok_long(GetLastError(), 0xbadbabe);
+
+    ok_long(CombineRgn(hrgn1, hrgn1, hrgn1, RGN_DIFF), NULLREGION);
+    ok_long(CombineRgn(hrgn1, hrgn2, hrgn2, RGN_DIFF), NULLREGION);
+    ok_long(CombineRgn(hrgn1, hrgn1, hrgn2, RGN_DIFF), NULLREGION);
+
+    ok_long(CombineRgn(hrgn1, hrgn2, hrgn1, RGN_DIFF), SIMPLEREGION);
+    ok_long(CombineRgn(hrgn1, hrgn2, hrgn3, RGN_DIFF), COMPLEXREGION);
+    ok_long(CombineRgn(hrgn1, hrgn1, hrgn3, RGN_DIFF), COMPLEXREGION);
+    ok_long(CombineRgn(hrgn1, hrgn1, hrgn2, RGN_DIFF), NULLREGION);
+
+
+}
+
+void Test_CombineRgn_XOR()
+{
+    HRGN hrgn1, hrgn2, hrgn3, hrgn4;
+
+    hrgn1 = CreateRectRgn(0, 0, 0, 0);
+    hrgn2 = CreateRectRgn(0, 0, 5, 5);
+    hrgn3 = CreateRectRgn(5, 5, 10, 10);
+    hrgn4 = CreateRectRgn(0, 0, 0, 0);
+
+    SetLastError(0xbadbabe);
+    ok_long(CombineRgn(NULL, NULL, NULL, RGN_XOR), ERROR);
+    ok_long(CombineRgn(hrgn1, NULL, NULL, RGN_XOR), ERROR);
+    ok_long(CombineRgn(hrgn1, hrgn2, NULL, RGN_XOR), ERROR);
+    ok_long(CombineRgn(hrgn1, NULL, hrgn2, RGN_XOR), ERROR);
+    ok_long(CombineRgn(hrgn1, GetStockObject(BLACK_PEN), hrgn2, RGN_XOR), ERROR);
+    ok_long(CombineRgn(hrgn1, hrgn2, GetStockObject(BLACK_PEN), RGN_XOR), ERROR);
+    ok_long(GetLastError(), 0xbadbabe);
+
+    ok_long(CombineRgn(hrgn1, hrgn2, hrgn3, RGN_XOR), COMPLEXREGION);
+    ok_long(CombineRgn(hrgn4, hrgn2, hrgn3, RGN_OR), COMPLEXREGION);
+    ok(EqualRgn(hrgn1, hrgn4), "Region is not correct\n");
+
+    ok_long(CombineRgn(hrgn1, hrgn1, hrgn2, RGN_XOR), SIMPLEREGION);
+    ok(EqualRgn(hrgn1, hrgn3), "Region is not correct\n");
+    ok_long(CombineRgn(hrgn1, hrgn1, hrgn3, RGN_XOR), NULLREGION);
+
+
+}
+
+START_TEST(CombineRgn)
+{
+    Test_CombineRgn_COPY();
+    Test_CombineRgn_AND();
+    Test_CombineRgn_OR();
+    Test_CombineRgn_DIFF();
+    Test_CombineRgn_XOR();
+}
+
diff --git a/rostests/apitests/gdi32/testlist.c b/rostests/apitests/gdi32/testlist.c
index 31c7f1d0168..5d45cab5ea6 100644
--- a/rostests/apitests/gdi32/testlist.c
+++ b/rostests/apitests/gdi32/testlist.c
@@ -8,6 +8,7 @@
 extern void func_AddFontResource(void);
 extern void func_AddFontResourceEx(void);
 extern void func_BeginPath(void);
+extern void func_CombineRgn(void);
 extern void func_CombineTransform(void);
 extern void func_CreateBitmap(void);
 extern void func_CreateBitmapIndirect(void);
@@ -61,6 +62,7 @@ const struct test winetest_testlist[] =
     { "AddFontResource", func_AddFontResource },
     { "AddFontResourceEx", func_AddFontResourceEx },
     { "BeginPath", func_BeginPath },
+    { "CombineRgn", func_CombineRgn },
     { "CombineTransform", func_CombineTransform },
     { "CreateBitmap", func_CreateBitmap },
     { "CreateBitmapIndirect", func_CreateBitmapIndirect },