diff --git a/CHANGES.md b/CHANGES.md
index 38d37a4a42..1e01d5b4aa 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -75,6 +75,7 @@ Bug Fixes
 * [#646](https://github.com/java-native-access/jna/issues/646): `platform.win32.COM.COMBindingBaseObject` swallows reason if instantiation fails - [@matthiasblaesing](https://github.com/matthiasblaesing).
 * [#674](https://github.com/java-native-access/jna/pull/674): Update references to Apache License as requested by issue #673 [@bhamail](https://github.com/bhamail)
 * [#636](https://github.com/java-native-access/jna/issues/636): Staticly link visual c++ runtime when building with MSVC - [@matthiasblaesing](https://github.com/matthiasblaesing).
+* [#624](https://github.com/java-native-access/jna/issues/624): WinDef.DWORD getLow() & getHigh() using incorrect bit mask - [@matthiasblaesing](https://github.com/matthiasblaesing).
 
 Release 4.2.1
 =============
diff --git a/contrib/platform/src/com/sun/jna/platform/win32/WinDef.java b/contrib/platform/src/com/sun/jna/platform/win32/WinDef.java
index ccae0a0ef5..181f513fa5 100644
--- a/contrib/platform/src/com/sun/jna/platform/win32/WinDef.java
+++ b/contrib/platform/src/com/sun/jna/platform/win32/WinDef.java
@@ -139,7 +139,7 @@ public DWORD(long value) {
          * @return Low WORD.
          */
         public WORD getLow() {
-            return new WORD(longValue() & 0xFF);
+            return new WORD(longValue() & 0xFFFF);
         }
 
         /**
@@ -148,7 +148,7 @@ public WORD getLow() {
          * @return High WORD.
          */
         public WORD getHigh() {
-            return new WORD((longValue() >> 16) & 0xFF);
+            return new WORD((longValue() >> 16) & 0xFFFF);
         }
 
         @Override
diff --git a/contrib/platform/test/com/sun/jna/platform/win32/Kernel32Test.java b/contrib/platform/test/com/sun/jna/platform/win32/Kernel32Test.java
index 1f42ef3773..61ba8076f5 100644
--- a/contrib/platform/test/com/sun/jna/platform/win32/Kernel32Test.java
+++ b/contrib/platform/test/com/sun/jna/platform/win32/Kernel32Test.java
@@ -346,7 +346,7 @@ public void testOpenProcess() {
 
     public void testQueryFullProcessImageName() {
         int pid = Kernel32.INSTANCE.GetCurrentProcessId();
-        HANDLE h = Kernel32.INSTANCE.OpenProcess(0, false, pid);
+        HANDLE h = Kernel32.INSTANCE.OpenProcess(WinNT.PROCESS_QUERY_INFORMATION, false, pid);
         assertNotNull("Failed (" + Kernel32.INSTANCE.GetLastError() + ") to get process ID=" + pid + " handle", h);
 
         try {
diff --git a/contrib/platform/test/com/sun/jna/platform/win32/WinDefTest.java b/contrib/platform/test/com/sun/jna/platform/win32/WinDefTest.java
new file mode 100644
index 0000000000..f2fb726ba9
--- /dev/null
+++ b/contrib/platform/test/com/sun/jna/platform/win32/WinDefTest.java
@@ -0,0 +1,44 @@
+
+package com.sun.jna.platform.win32;
+
+import com.sun.jna.platform.win32.WinDef.DWORD;
+import com.sun.jna.platform.win32.WinDef.WORD;
+import org.junit.Test;
+import static org.junit.Assert.*;
+
+public class WinDefTest {
+
+    @Test
+    public void testWordExtractionFromDword() {
+        DWORD dword = new DWORD(0x12345678);
+        
+        assertEquals(new WORD(0x5678), dword.getLow());
+        assertEquals(new WORD(0x1234), dword.getHigh());
+
+        DWORD dword2 = new DWORD(0xFFFFFFFF);
+        
+        assertEquals(new WORD(0xFFFF), dword2.getLow());
+        assertEquals(new WORD(0xFFFF), dword2.getHigh());
+      
+        DWORD dword3 = new DWORD(0x00000001);
+        
+        assertEquals(new WORD(0x0001), dword3.getLow());
+        assertEquals(new WORD(0x0000), dword3.getHigh());
+        
+        DWORD dword4 = new DWORD(0x00010000);
+        
+        assertEquals(new WORD(0x0000), dword4.getLow());
+        assertEquals(new WORD(0x0001), dword4.getHigh());
+      
+        DWORD dword5 = new DWORD(0x0000FFFF);
+        
+        assertEquals(new WORD(0xFFFF), dword5.getLow());
+        assertEquals(new WORD(0x0000), dword5.getHigh());
+        
+        DWORD dword6 = new DWORD(0xFFFF0000);
+        
+        assertEquals(new WORD(0x0000), dword6.getLow());
+        assertEquals(new WORD(0xFFFF), dword6.getHigh());
+    }
+    
+}