Perinephric abscess is an accumulation of pus in the perinephric space, the area anatomically defined between the kidney and Gerota's fascia. Gram negative organisms are the most prevalent bacterial species found in perinephric abscess. Fever, flank pain, vomiting and abdominal mass are the usual presenting complaints. But with its insidious onset, variable symptoms and rare frequency in children, perinephric abscess has been a major diagnostic problem, leading to delayed diagnosis and inappropriate treatment, which increase the rate of complication and mortality. Clinical diagnosis of perinephric abscess is difficult but must always be considered in children with a febrile septicemic illness. For appropriate treatment, early detection is very important, and either ultrasonography or computed tomography(CT) facilitates the diagnosis and establishment of treatment method. We experienced a case of left perinephric abscess treated by percutaneous drainage in a 1-year 7-month old boy. Review of literature was made briefly.