Twenty-eight Hartley strain guinea pigs were divided into three groups. Group I animals had their exteriorized testes torsed for a variable period of time until a bluish black color was maintained after detorsion. Group II and III animals served as controls. Testicular hormone function was estimated by analysis of accessory sex gland weights and citric acid and fructose content. Spermatogenesis was assessed by testicular histology and sorbitol dehydrogenase activity and epididymal sperm number and motility. No apparent effect on either spermatogenic or hormonal function of the guinea pig testis resulted from the torsion of the spermatic cord to the degree and length of time described.