diff --git a/GaudiKernel/GaudiKernel/ITHistSvc.h b/GaudiKernel/GaudiKernel/ITHistSvc.h
index ae2e161385540323526e37ea01e64fa525362d97..e5430828d60e47da5eb219fe04b6fc228392c07a 100644
--- a/GaudiKernel/GaudiKernel/ITHistSvc.h
+++ b/GaudiKernel/GaudiKernel/ITHistSvc.h
@@ -20,7 +20,7 @@ class TList;
 class TDirectory;
 class TGraph;
 
-class ITHistSvc : virtual public IService
+class GAUDI_API ITHistSvc : virtual public IService
 {
 public:
   /// InterfaceID