Dibutyltin dilaurate is extracted from finished feed with warm chloroform. The chloroform extract is filtered and a 25 ml aliquot is concentrated in the presence of methanol until all traces of chloroform are removed. The methanol solution is diluted and feed interferences are removed by filtration. The filtered solution is aspirated into an atomic absorption spectrophotometer with a triple-slot burner head, using an air-acetylene flame. The instrument response to tin at 286.3 nm is recorded. Essentially theoretical recovery (100.5— 101.9%) has been obtained for tin in laboratory-mixed feeds.