diff --git a/include/osg/Node b/include/osg/Node
index f2be03e72..2174c4e9b 100644
--- a/include/osg/Node
+++ b/include/osg/Node
@@ -165,14 +165,14 @@ class OSG_EXPORT Node : public Object
         inline const NodeCallback* getUpdateCallback() const { return _updateCallback.get(); }
 
         /** Convenience method that sets the update callback of the node if it doesn't exist, or nest it into the existing one. */
-        void addUpdateCallback(NodeCallback* nc) {
+        inline void addUpdateCallback(NodeCallback* nc) {
             if (_updateCallback.valid()) _updateCallback->addNestedCallback(nc);
             else setUpdateCallback(nc);
         }
 
         /** Convenience method that removes a given callback from a node, even if that callback is nested. There is no error return in case the given callback is not found. */
-        void removeUpdateCallback(NodeCallback* nc) {
-            if (_updateCallback == nc) setUpdateCallback(nc->getNestedCallback());		// replace the callback by the nested one
+        inline void removeUpdateCallback(NodeCallback* nc) {
+            if (_updateCallback == nc) setUpdateCallback(nc->getNestedCallback());        // replace the callback by the nested one
             else _updateCallback->removeNestedCallback(nc);
         }
 
@@ -191,14 +191,14 @@ class OSG_EXPORT Node : public Object
         inline const NodeCallback* getEventCallback() const { return _eventCallback.get(); }
 
         /** Convenience method that sets the event callback of the node if it doesn't exist, or nest it into the existing one. */
-        void addEventCallback(NodeCallback* nc) {
+        inline void addEventCallback(NodeCallback* nc) {
             if (_eventCallback.valid()) _eventCallback->addNestedCallback(nc);
             else setEventCallback(nc);
         }
 
         /** Convenience method that removes a given callback from a node, even if that callback is nested. There is no error return in case the given callback is not found. */
-        void removeEventCallback(NodeCallback* nc) {
-            if (_eventCallback == nc) setEventCallback(nc->getNestedCallback());		// replace the callback by the nested one
+        inline void removeEventCallback(NodeCallback* nc) {
+            if (_eventCallback == nc) setEventCallback(nc->getNestedCallback());        // replace the callback by the nested one
             else _eventCallback->removeNestedCallback(nc);
         }
 
@@ -217,14 +217,14 @@ class OSG_EXPORT Node : public Object
         inline const NodeCallback* getCullCallback() const { return _cullCallback.get(); }
 
         /** Convenience method that sets the cull callback of the node if it doesn't exist, or nest it into the existing one. */
-        void addCullCallback(NodeCallback* nc) {
+        inline void addCullCallback(NodeCallback* nc) {
             if (_cullCallback.valid()) _cullCallback->addNestedCallback(nc);
             else setCullCallback(nc);
         }
 
         /** Convenience method that removes a given callback from a node, even if that callback is nested. There is no error return in case the given callback is not found. */
-        void removeCullCallback(NodeCallback* nc) {
-            if (_cullCallback == nc) setCullCallback(nc->getNestedCallback());		// replace the callback by the nested one
+        inline void removeCullCallback(NodeCallback* nc) {
+            if (_cullCallback == nc) setCullCallback(nc->getNestedCallback());        // replace the callback by the nested one
             else _cullCallback->removeNestedCallback(nc);
         }