The authors evaluate the testicular blood flow by Doppler stethoscope in 90 infants and children; they tell two indications: In emergency the most common is "acute scrotal swelling": 78 cases, 4 false negative are reported in diagnosis of torsion of the spermatic cord; the limit of the Doppler examination are the possibility of a interepididymo-testicular torsion and, above all, the inflammation of the scrotal wall. If Doppler examination are in agreement, unnecessary surgical explorations must be avoided. Outside emergency, Doppler examination may be help-full to evaluate varicocele and to control some surgical operation involving spermatic cord (12 cases).