An efficient method for the synthesis of pseudodipeptides, which combines an aza glycine residue with various hydrazinoacid moieties by simple substitution of the halogen of α-halohydrazides, is described. Some of these hydrazinoazapeptides lead to hydrazones by oxidation or to azaaminouracils by cyclization.Key words: hydrazinohydrazides, hydrazones, hydrazinoazapeptides, azaaminouracils, pseudopeptides.