The product of base-catalysed condensation of benzaldehyde and malonamide is the complex Schiff base β-(benzylideneimino) benzylmalonamide, rather than benzylidenemalonamide as previously reported. Analogous Schiff bases are formed from aliphatic as well as aromatic aldehydes. Benzylidenemaloanamide itself is formed from β- (benzylidene The mass spectra of this compound and the Schiff bases are analysed.