diff --git a/CHANGES.md b/CHANGES.md
index 5661442aea..a0dbd74f0f 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -47,6 +47,7 @@ Features
 * [#616](https://github.com/java-native-access/jna/pull/616): Allow access to base interfaces (most important IDispatch) via ProxyObject and improve binding by allowing to use dispId for the call - [@matthiasblaesing](https://github.com/matthiasblaesing).
 * [#621](https://github.com/java-native-access/jna/pull/621): Added TYPEFLAGS-constants for `wTypeFlags` in `com.sun.jna.platform.win32.OaIdl.TYPEATTR` - [@SevenOf9Sleeper](https://github.com/SevenOf9Sleeper).
 * [#625](https://github.com/java-native-access/jna/pull/625): Make conversion to/from java to/from VARIANT in `com.sun.jna.platform.win32.COM.util.Convert` more flexible and dependable - [@matthiasblaesing](https://github.com/matthiasblaesing).
+* [#639](https://github.com/java-native-access/jna/pull/639): Add getloadavg() to OS X and Unix - [@dbwiddis](https://github.com/dbwiddis).
 
 Bug Fixes
 ---------
diff --git a/contrib/platform/src/com/sun/jna/platform/mac/SystemB.java b/contrib/platform/src/com/sun/jna/platform/mac/SystemB.java
index a1d6b682bb..c4dfd7cbd7 100644
--- a/contrib/platform/src/com/sun/jna/platform/mac/SystemB.java
+++ b/contrib/platform/src/com/sun/jna/platform/mac/SystemB.java
@@ -168,6 +168,15 @@ protected List<String> getFieldOrder() {
      * @return the host's name port
      */
     int mach_host_self();
+    
+    /**
+     * The mach_task_self system call returns the calling thread's task_self
+     * port. It has an effect equivalent to receiving a send right for the task's
+     * kernel port.  
+     *
+     * @return the task's kernel port
+     */
+    int mach_task_self();
 
     /**
      * The host_page_size function returns the page size for the given host.
@@ -333,4 +342,20 @@ int sysctlbyname(String name, Pointer oldp, IntByReference oldlenp,
      */
     int host_processor_info(int machPort, int flavor, IntByReference procCount,
         PointerByReference procInfo, IntByReference procInfoCount);
+    
+    /**
+     * The getloadavg() function returns the number of processes in the system
+     * run queue averaged over various periods of time.  Up to nelem samples are
+     * retrieved and assigned to successive elements of loadavg[].  The system
+     * imposes a maximum of 3 samples, representing averages over the last 1, 5,
+     * and 15 minutes, respectively.
+     * @param loadavg
+     *            An array of doubles which will be filled with the results
+     * @param nelem
+     *            Number of samples to return
+     * @return If the load average was unobtainable, -1 is returned; otherwise, 
+     * the number of samples actually retrieved is returned.
+     * @see <A HREF="https://www.freebsd.org/cgi/man.cgi?query=getloadavg&sektion=3">getloadavg(3)</A>
+     */
+    int getloadavg(double[] loadavg, int nelem);
 }
diff --git a/contrib/platform/src/com/sun/jna/platform/unix/LibCAPI.java b/contrib/platform/src/com/sun/jna/platform/unix/LibCAPI.java
index 9418abacb4..888701240f 100644
--- a/contrib/platform/src/com/sun/jna/platform/unix/LibCAPI.java
+++ b/contrib/platform/src/com/sun/jna/platform/unix/LibCAPI.java
@@ -73,4 +73,18 @@ public interface LibCAPI extends Reboot, Resource {
      * @see <A HREF="https://www.freebsd.org/cgi/man.cgi?query=setenv&sektion=3">getenv(3)</A>
      */
     int unsetenv(String name);
+    
+    /**
+     * The getloadavg() function returns the number of processes in the system
+     * run queue averaged over various periods of time.  Up to nelem samples are
+     * retrieved and assigned to successive elements of loadavg[].  The system
+     * imposes a maximum of 3 samples, representing averages over the last 1, 5,
+     * and 15 minutes, respectively.
+     * @param loadavg An array of doubles which will be filled with the results
+     * @param nelem Number of samples to return
+     * @return If the load average was unobtainable, -1 is returned; otherwise, 
+     * the number of samples actually retrieved is returned.
+     * @see <A HREF="https://www.freebsd.org/cgi/man.cgi?query=getloadavg&sektion=3">getloadavg(3)</A>
+     */
+    int getloadavg(double[] loadavg, int nelem);
 }
diff --git a/contrib/platform/test/com/sun/jna/platform/mac/SystemBTest.java b/contrib/platform/test/com/sun/jna/platform/mac/SystemBTest.java
index 1b11b5cd5c..0ac161e0d4 100644
--- a/contrib/platform/test/com/sun/jna/platform/mac/SystemBTest.java
+++ b/contrib/platform/test/com/sun/jna/platform/mac/SystemBTest.java
@@ -152,7 +152,23 @@ public void testHostProcessorInfo() {
 		assertEquals(procCpuLoadInfo.getValue().getIntArray(0,
 				procInfoCount.getValue()).length, procInfoCount.getValue());
 	}
-
+	
+    public void testMachPorts() {
+      int machPort = SystemB.INSTANCE.mach_host_self();
+      assertTrue(machPort > 0);
+      machPort = SystemB.INSTANCE.mach_task_self();
+      assertTrue(machPort > 0);	  
+      }
+
+    public void testGetLoadAvg() {
+      double[] loadavg = new double[3];
+      int retval = SystemB.INSTANCE.getloadavg(loadavg, 3);
+      assertEquals(retval, 3);
+      assertTrue(loadavg[0] >= 0);
+      assertTrue(loadavg[1] >= 0);
+      assertTrue(loadavg[2] >= 0);
+    }
+	
 	public static void main(java.lang.String[] argList) {
 		junit.textui.TestRunner.run(SystemBTest.class);
 	}
diff --git a/contrib/platform/test/com/sun/jna/platform/unix/LibCTest.java b/contrib/platform/test/com/sun/jna/platform/unix/LibCTest.java
index 6a7539a6aa..5c5efa93b9 100644
--- a/contrib/platform/test/com/sun/jna/platform/unix/LibCTest.java
+++ b/contrib/platform/test/com/sun/jna/platform/unix/LibCTest.java
@@ -48,4 +48,14 @@ public void testSetenv() {
             LibC.INSTANCE.unsetenv(name);
         }
     }
+    
+    @Test
+    public void testGetLoadAvg() {
+        double[] loadavg = new double[3];
+        int retval = LibC.INSTANCE.getloadavg(loadavg, 3);
+        assertEquals(retval, 3);
+        assertTrue(loadavg[0] >= 0);
+        assertTrue(loadavg[1] >= 0);
+        assertTrue(loadavg[2] >= 0);
+    }
 }