Renal abscess is uncommon in childhood and requires hospitalization, drainage and antibiotic therapy. In this paper, we report two children with renal abscess treated only with antibiotic therapy. The diagnosis had been made by ultrasonography and computed tomography. During the period of treatment a series of ultrasonography were performed to monitor resolution of abscess. The renal abscess in childhood treated in the right time and in the right way have good prognosis for the kidney and the patient.