Urinary ascites is a rare diagnosis usually associated with intra-peritoneal bladder perforation. We present a case of massive urinary ascites in a patient who presented 1 week after a total abdominal hysterectomy and sacrocolpopexy. We discuss how the diagnosis was made, the mechanism of biochemical changes associated with urinary ascites and the management. In summary, we show that a combination of serum and ascitic biochemistry are essential to make a diagnosis of urinary ascites.