Our objective was to assess the differential diagnostic value of classification of obstructive versus nonobstructive azoospermia by scrotal ultrasound. Forty patients with azoospermia were selected for our study (ages, 23–35; average, 29 ± 5.34 years). Patients were divided into the obstructive (17) or nonobstructive (23) azoospermia category. Twenty “healthy” volunteers were selected for the control group. We observed the testis, epididymis, and vas deferens in all subjects. Testicular volumes were calculated and compared with the control group for both obstructive and nonobstructive groups. Cystic or tubular dilation of the epididymis was found in all patients with obstructive azoospermia. The patients with nonobstructive azoospermia had no significant abnormalities of the epididymis. There was no difference in the testicular volumes between the patients with obstructive azoospermia and healthy controls (P > 0.05). However, the testicular volumes of patients with nonobstructive azoospermia were smaller than those of healthy volunteers (P < 0.05). It is helpful to identify obstructive and nonobstructive azoospermia by scrotal ultrasound, because it is a less invasive method that can be used to isolate probable treatment options.