Symptomatic lymphocele presented after pelvic lymphadenectomy for localized carcinoma of the prostate is a relatively rare complication. We treated a case of infected lymphocele presenting 4 months after a limited staging pelvic lymphadenectomy and a radical prostatectomy for adenocarcinoma of the prostate. The patient was a 70-year-old Japanese man having the chief complaint of fever, right lower abdominal pain, nausea and vomiting. Pelvic computed tomography showed a 14 cm cystic mass with a thick capsule on the right iliopsoas muscle. It was suspected to be an infected lymphocele. After percutaneous drainage, sclerotherapy (povidone iodine, minocycline and ethanol) and antibiotic drugs, the infected lymphocele was resolved.