Organo-tin hydrides of the formula RmSnH4- m where R represents an alkyl and/or aryl group and m = 1, 2 or 3 are stabilized by hydrolysis and/or alcoholysis which removes impurities. The hydrolysis and/or alcoholysis may be carried out in the presence of an acid binding agent, e.g. ammonia, alkali metal or alkaline earth metal hydroxides or carbonates, or organic amines. The alcoholysis may be carried out using methanol, butyl alcohol or 2 ethyl hexanol. The subject-matter of Specification 951,150 is disclaimed.