diff --git a/compiler/nobj.pas b/compiler/nobj.pas
index 582e54609f..df059347c0 100644
--- a/compiler/nobj.pas
+++ b/compiler/nobj.pas
@@ -1105,6 +1105,7 @@ implementation
     procedure tclassheader.gintfdoonintf(intf: tobjectdef; intfindex: longint);
       var
         def: tdef;
+        hs,
         mappedname: string;
         nextexist: pointer;
         implprocdef: tprocdef;
@@ -1117,7 +1118,8 @@ implementation
                 implprocdef:=nil;
                 nextexist:=nil;
                 repeat
-                  mappedname:=_class.implementedinterfaces.getmappings(intfindex,tprocdef(def).procsym.name,nextexist);
+                  hs:=intf.symtable.name^+'.'+tprocdef(def).procsym.name;
+                  mappedname:=_class.implementedinterfaces.getmappings(intfindex,hs,nextexist);
                   if mappedname<>'' then
                     implprocdef:=gintfgetcprocdef(tprocdef(def),mappedname);
                 until assigned(implprocdef) or not assigned(nextexist);
diff --git a/compiler/pdecsub.pas b/compiler/pdecsub.pas
index a145afe710..8f7cb5e9c5 100644
--- a/compiler/pdecsub.pas
+++ b/compiler/pdecsub.pas
@@ -635,6 +635,7 @@ implementation
 
     function parse_proc_head(aclass:tobjectdef;potype:tproctypeoption;var pd:tprocdef):boolean;
       var
+        hs       : string;
         orgsp,sp : stringid;
         sym : tsym;
         srsym : tsym;
@@ -690,9 +691,11 @@ implementation
            if (i=-1) then
              Message(parser_e_interface_id_expected);
            consume(_ID);
+           { Create unique name <interface>.<method> }
+           hs:=sp+'.'+pattern;
            consume(_EQUAL);
            if (token=_ID) then
-             aclass.implementedinterfaces.addmappings(i,sp,pattern);
+             aclass.implementedinterfaces.addmappings(i,hs,pattern);
            consume(_ID);
            result:=true;
            exit;
diff --git a/compiler/symdef.pas b/compiler/symdef.pas
index ae215e5dbb..9d822733ce 100644
--- a/compiler/symdef.pas
+++ b/compiler/symdef.pas
@@ -285,8 +285,8 @@ interface
           procedure addintf_deref(const d:tderef;iofs:longint);
 
           procedure clearmappings;
-          procedure addmappings(intfindex: longint; const name, newname: string);
-          function  getmappings(intfindex: longint; const name: string; var nextexist: pointer): string;
+          procedure addmappings(intfindex: longint; const origname, newname: string);
+          function  getmappings(intfindex: longint; const origname: string; var nextexist: pointer): string;
 
           procedure addimplproc(intfindex: longint; procdef: tprocdef);
           function  implproccount(intfindex: longint): longint;
@@ -5063,7 +5063,7 @@ implementation
 
     constructor tnamemap.create(const aname, anewname: string);
       begin
-        inherited createname(name);
+        inherited createname(aname);
         newname:=stringdup(anewname);
       end;
 
@@ -5237,25 +5237,25 @@ implementation
             end;
       end;
 
-    procedure timplementedinterfaces.addmappings(intfindex: longint; const name, newname: string);
+    procedure timplementedinterfaces.addmappings(intfindex: longint; const origname, newname: string);
       begin
         checkindex(intfindex);
         with timplintfentry(finterfaces.search(intfindex)) do
           begin
             if not assigned(namemappings) then
               namemappings:=tdictionary.create;
-            namemappings.insert(tnamemap.create(name,newname));
+            namemappings.insert(tnamemap.create(origname,newname));
           end;
       end;
 
-    function  timplementedinterfaces.getmappings(intfindex: longint; const name: string; var nextexist: pointer): string;
+    function  timplementedinterfaces.getmappings(intfindex: longint; const origname: string; var nextexist: pointer): string;
       begin
         checkindex(intfindex);
         if not assigned(nextexist) then
           with timplintfentry(finterfaces.search(intfindex)) do
             begin
               if assigned(namemappings) then
-                nextexist:=namemappings.search(name)
+                nextexist:=namemappings.search(origname)
               else
                 nextexist:=nil;
             end;