Patients receiving maintenance dialysis have higher mortality after primary percutaneous coronary intervention (pPCI) than patients not receiving dialysis. Whether pPCI confers a benefit to patients receiving dialysis that is similar to that which occurs in lower-risk groups remains unknown. We compared the effect of pPCI on in-hospital outcomes among patients hospitalized for ST-elevation myocardial infarction (STEMI) and receiving maintenance dialysis with the effect among patients hospitalized for STEMI but not receiving dialysis.