Leydig cell testicular tumors are very rare in children and cause isosexual precocious puberty. Palpable testicular mass or asymmetric testes are common findings on routine examination. We report on a 5-yr-old boy with a Leydig cell tumor of the testis presented with isosexual precocious puberty but no scrotal palpable mass. To our knowledge, this is the first reported Leydig cell tumor in a boy without palpable scrotal mass.