A consecutive series of 100 boys with 104 impalpable testes is reviewed. Extended inguinal exploration was the main form of investigation and treatment. Hormone injections and studies were performed in bilateral cases and in the latter part of the series, laparoscopy supplemented inguinal operation. Sonography was unhelpful. Seventy-five testes were found, 34 in the abdomen, 34 in the inguinal canal, and 7 below the external ring. Seventeen of the abdominal testes, 31 of the inguinal testes, and all of those below the external ring were successfully brought to the scrotum. In ten boys no trace of testis was found and in 19 there was testicular or cord "remnant." Laparoscopy was performed before inguinal exploration in eight and it is concluded that this procedure is helpful but of limited value. It is indicated where no testis or testicular vessels are found on inguinal exploration and this occurs in about 15% of impalpable testes. When an atrophic testis is found, it is not evident whether the testis is agenetic or whether its disappearance resulted from torsion so fixation of the contralateral testis is recommended in all such patients.