Late referral to nephrologists of patients with chronic kidney disease (CKD) is a major public health problem because it is prevalent and associated with increased morbidity, mortality, and greater healthcare costs. To identify factors associated with delayed nephrologist referral (first nephrologist visit < 90 days before the onset of renal replacement therapy), we identified a cohort of patients with preexisting CKD that progressed to end-stage renal failure. We developed a logistic regression model to measure the association of specific demographic and clinical covariates with delayed nephrologist referral. Delayed referral was highly associated with older age (P < 0.001), race other than white or black (P = 0.002), and the absence of certain comorbidities: hypertension (P < 0.001), coronary artery disease (P < 0.001), malignancy (P = 0.005), and diabetes (P = 0.02). Associations of late referral with male sex (P = 0.07) and lower socioeconomic status (P = 0.09) were of borderline significance. Patients who were predominantly cared for by a general internist were more likely to be referred late to a nephrologist compared with those cared for by a family or primary care practitioner (P = 0.002) or another subspecialist (P = 0.019). These findings suggest that several factors increase the risk that patients with CKD will have the first nephrologist consultation excessively late in the course of their disease. Although timely access to nephrologist services is important for all patients with advanced CKD, this is of particular concern in older patients, those in certain minority populations, and those in whom the absence of comorbidity may provide a false sense of true risk status.