Prune belly syndrome (PBS) is a rare congenital syndrome characterised by a triad of deficiency of abdominal wall muscles, undescended testis and dilated urinary tract. It may be related to lower urinary tract obstruction with renal dysfunction. Early and accurate diagnosis with proper treatment is important to prevent renal impairment. We report Ultrasound (US) and Magnetic Resonance Imaging (MRI) findings of a case of prune belly syndrome diagnosed at 20 weeks of gestation. US showed grossly dilated fetal urinary bladder, dilated ureters and kidneys with no identifiable renal parenchyma, mild ascites and severe oligohydramnios. Fetal MRI confirmed the ultrasound findings.