Lymphocele is a rare symptomatic complication of iliopelvic lymph node dissection during radical prostatectomy. The authors report a case of pelvic lymphocele with perirenal extension diagnosed 6 months after the operation and successfully treated by laparoscopic marsupialisation. The possibility of lymphocele must be considered in any patient presenting with abdominopelvic symptoms after iliopelvic lymph node dissection, even several months after the operation. The treatment of choice is laparoscopic marsupialisation, in the absence of infection.