Cancer patients with severe renal dysfunction represent a challenge for the physician. This is the first case report on the use of denosumab in a dialysis patient with bone metastases. We present the clinical case of a 45-year-old woman who had hepatorenal polycystic disease, diagnosed during childhood, and stage IV chronic kidney failure at the time of breast cancer diagnosis. Three years after surgery plus adjuvant hormonal therapy she suffered a further worsening of renal function, requiring dialysis, and very advanced bone metastasis in the hip with severe pain. As pamidronate was the only bone agent available in the center, she received it for 4 months (before a dialysis session), during which time the bone metastases stabilized. In March 2014, the patient switched to denosumab (which had become available in the center), and continued with hormone therapy. Seven months after denosumab initiation, the patient had almost complete pain relief, and the bone metastases exhibited radiological improvement. The tolerability was excellent, without any related adverse event. There were no changes in albumin-adjusted serum calcium, serum phosphorus, and intact parathyroid hormone, except for a transient and mild hypocalcemia at 3 months and an increase in intact parathyroid hormone levels, which required adjustment of vitamin D analog dose. Denosumab can be administered to prevent skeletal-related events in patients with bone metastasis from solid tumors and severely impaired renal function, even in those requiring dialysis. In this particular patient, the safety was good.