Complement of an IntervalValued Fuzzy Graph (IVFG) was defined byTalebi and Rashmanlou [7]. We observed that their definition fails in some cases and we reformulated the notion of complement in such a way that it applies to all IVFG's. We also introduced the concepts of Classic and Non-classic IVFG's, and Perfect and Imperfect edges of an IVFG and state some theorems regarding these concepts.