diff --git a/dlls/cryptui/cryptui.spec b/dlls/cryptui/cryptui.spec
index aa4b00a44a8..b023ed2ab61 100644
--- a/dlls/cryptui/cryptui.spec
+++ b/dlls/cryptui/cryptui.spec
@@ -1,5 +1,5 @@
 1 stub ACUIProviderInvokeUI
-2 stub CryptUIDlgCertMgr
+2 stdcall CryptUIDlgCertMgr(ptr)
 3 stub CryptUIDlgFreeCAContext
 4 stub CryptUIDlgSelectCA
 5 stub CryptUIDlgSelectCertificateA
diff --git a/dlls/cryptui/main.c b/dlls/cryptui/main.c
index a951f013dc4..87849156e5c 100644
--- a/dlls/cryptui/main.c
+++ b/dlls/cryptui/main.c
@@ -22,6 +22,8 @@
 
 #include "windef.h"
 #include "winbase.h"
+#include "winuser.h"
+#include "cryptuiapi.h"
 #include "wine/debug.h"
 
 WINE_DEFAULT_DEBUG_CHANNEL(cryptui);
@@ -44,3 +46,12 @@ BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved)
     }
     return TRUE;
 }
+
+/***********************************************************************
+ *		CryptUIDlgCertMgr (CRYPTUI.@)
+ */
+BOOL WINAPI CryptUIDlgCertMgr(PCCRYPTUI_CERT_MGR_STRUCT pCryptUICertMgr)
+{
+    FIXME("(%p): stub\n", pCryptUICertMgr);
+    return FALSE;
+}