A one day old full term twin boy presented with an abdominal left testis and a scrotal right testis both of which had a normal histological appearance. A gubernaculum with normal macroanatomy and histology was found in the left inguinal canal but no processus vaginalis could be detected. Both of his brother's testes were normally descended. It is suggested that the abdominal position of the left testis was caused by a failing gubernacular reaction due to a local hormone insensitivity.