Wunderlich syndrome, or spontaneous renal hemorrhage (SRH), is a rare condition encountered in patients undergoing chronic hemodialysis (HD) usually attributed to acquired cystic kidney disease (ACKD) among other causes. In the literature, colonoscopy is associated with splenic injuries, and renal hemorrhage has not been previously described. Management can range from conservative treatment to angiographic embolization or exploration and nephrectomy. Here we report an unusual case of a 54-year-old woman HD patient who presented with SRH within a few days of colonoscopy. The reason of SRH was rupture of an ACKD cyst. We assumed that colonoscopy was a provoking factor and elaborated hypotheses for its etiopathogenesis. The patient underwent successful left nephrectomy. The importance of this case lies in the fact that colonoscopy is not always an innocent procedure in HD patients, and could be complicated by renal cyst hemorrhage.