The contralateral internal inguinal rings of 333 children were examined with a laparoscope during repair of unilateral inguinal hernia. The nonpuncture laparoscopy technique was used so that no extra wound was created. The morphology of the rings was classified as follows: type 1, flat and covered tightly with peritoneum; type 2, shallow with a visible base under an elevated peritoneal fold; type 3, deep ring that represented a patent processus vaginalis. The incidence of types 1, 2, and 3 rings was 45%, 23%, and 32%, respectively. The incidence of type 1 internal rings was similar for different age groups. The incidence of type 2 rings increased with age, and that of type 3 decreased with age. This observation is compatible with autopsy studies and the experience of contralateral exploration of childhood inguinal hernias.