Acquired cystic kidney disease (ACKD) is a complication of end-stage renal disease, the prevalence of which is related to dialysis duration; incidence of ACKD and associated conditions (neoplasia, hemorrhage) have decreased with improvements in renal transplantation and with the ageing of the dialysis population. This report regards spontaneous kidney rupture in a 57-year old patient, on home hemodialysis for 11 years, with ACKD for 5 years. At the end of a dialysis session, the patient reported sudden onset of colicky flank pain, followed by macrohematuria. Pain remitted with low doses of pain relievers, leaving dull flank discomfort. The patient self diagnosed a renal colic, and called the hospital two days later. At referral, two large hemorrhagic renal masses (7 and 2.8 cm) were found at ultrasound and CT scan. At surgery, kidney rupture was diagnosed. This case highlights the life threatening complications associated with ACKD, and underlines that massive renal hemorrhage may occur with relatively minor symptoms.