Background. Abdominoscrotal sonogram is often used in boys with a nonpalpable testis to determine the presence of the testis. We describe our experience with the use of ultrasonography in boys with a nonpalpable testis. Methods. We retrospectively reviewed the medical records of boys aged less than 14 years, who underwent preoperative ultrasonography for an impalpable undescended testis (IUDT) between 2006 and 2010 in our institution. The results of sonography and laparoscopy were compared. Results. A total of 26 impalpable testes in 22 patients, including 4 with bilateral impalpable testes, were preoperatively assessed by ultrasonography for their localization. Sonography localized only 6 of the 26 (23%) testes, which were laparoscopically explored and followed by orchiopexy. Conclusion. Ultrasound is not reliable in the preoperative assessment of patients with impalpable testes.