Organotin carboxylates of general formula R3SnL (1), (2), (4) and (6), R2SnL2 (5) and {[(R2SnL)(2)O](2)} (3), where L = N-maleoylglycinate, N-maleoyl-beta-alaninate and N-maleoylmethioninate, were prepared. The synthesis of these compounds was achieved by either reaction of organotin halides, R3SnCl, with triethylammonium salt of N-maleoylamino acids or/and organotin oxides, (R3Sn)(2)O and R2SnO, with maleamic acid in the presence of triethyl amine. These compounds were characterized by FT-IR, multinuclear NMR (H-1, C-13 and Sn-119), mass and Sn-119m Mossbauer spectroscopy. The geometry around the tin atom is compared both in solution and in solid state. Different literature methods were employed to calculate the C-Sn-C angle in non-coordinating solvents. The mass fragmentation pattern demonstrated the McLafferty rearrangement in compound (6). Salient features of the X-ray structures for (1), (4) and (6) are also given.