The intestinal uptake site, enterohepatic circulation, and excretion into bile, feces, and urine of alkyltins (tetra‐ and trialkyltin) were investigated after oral, sc, or intestinal administration of the compounds to rats and rabbits. Assays of tetra‐ and trialkyltins in biological materials were carried out by gas chromatography. The main uptake sites in the small intestine were the jejunum and duodenum for tetraalkyltins and the ileum and jejunum for trialkyltins. Tetra‐ and trialkyltins were detected in the small intestine and contents of the intestinal lumen after sc injection of these compounds in rats. These facts suggest that tetra‐ and trialkyltins are transported in the body through enterohepatic circulation. The route, rate, and amount of excretion of tetra‐and trialkyltins seem to depend on the velocity of dealkylation, doses, physical and chemical properties, and route of administration of the compounds.