Cardiovascular death is the leading cause of mortality in patients undergoing hemodialysis. However, traditional risk factors, such as diabetes, hypertension, and other comorbidities, do not fully account for this excess risk. Uremic toxins, substances that accumulate in patients with kidney failure, may be responsible for accelerated cardiovascular disease. However, these uremic toxins remain largely undefined. The goal of our pilot study was to determine if an untargeted metabolomic approach could identify metabolites associated with cardiac death in patients on dialysis.