Some novel organoperoxo complexes of tin were prepared by the oxidative addition of dioxygen with Sn 2+. These are the first reported examples of this kind. The complexes isolated have the compositions [Sn(O2)2.2L], [Sn(O2)2L′], [Sn(O2)L′′2], [Sn(O2)C5H3N(COO)2H2O] and [Sn(O2)2L′′′] (L = pyridine, pyridine N-oxide, triphenylphosphine oxide, aniline; L′ = ethylenediamine, 2-aminopyridine, o-phenylenediamine; L′′ = pyridine-2-carboxylato, 2-aminophenolato, quinolin-8-olato, glycinato; L′′′ = diethylenetriamine and triethylenetetramine). The complexes were characterized by elemental analysis, conductivity measurements and infrared spectroscopic studies. None of these complexes showed oxygen transfer reactions. The ν1(O-O) stretching frequencies appear at 805-820 cm-1 , and are significantly insensitive to the choice of the coligands used. Extensive pp-dp bonding in the complexes renders absolute kinetic stability to the complexes.