diff --git a/caps/src/nsCertificatePrincipal.cpp b/caps/src/nsCertificatePrincipal.cpp
index 41129508d02b..b3d43eff6f5e 100644
--- a/caps/src/nsCertificatePrincipal.cpp
+++ b/caps/src/nsCertificatePrincipal.cpp
@@ -102,7 +102,7 @@ nsCertificatePrincipal::HashValue(PRUint32 *result)
     return NS_OK;
 }
 
-nsresult
+NS_IMETHODIMP
 nsCertificatePrincipal::Init(const char* data)
 {
     // Parses preference strings of the form