A national sample of dialysis physicians was used to obtain data for a comparison of patient characteristics, comorbid conditions and treatment patterns associated with the five leading causes of end-stage renal disease (ESRD). The data are used to assess trends in physician care for ESRD patients and likely changes in program costs. The analysis shows that patients with glomerulonephritis are the youngest. Those with hypertensive nephropathy are the oldest, and include the highest proportion of blacks, while those with polycystic kidney disease include the lowest proportion of blacks. Patients with diabetic nephropathy have the most problems noted at the time of physician contact, the most emergent and severe problems, the highest number of diagnostic tests utilized, the most complex treatments required and the longest physician time spent per encounter. Patients with ‘other interstitial nephritis’ are significantly more likely to have infections, musculoskeletal disorders, chronic obstructive pulmonary disease and neoplasms noted as comorbid conditions. They also have the highest number of therapeutic procedures and the greatest percentage of referrals for consultations. Survey data highlight the evolving nature of Medicare’s ESRD program. With increasing numbers of elderly and diabetic patients, more physician time will be required for the overall care of the dialysis patient, and increasing costs associated with necessary diagnostic tests and referrals can be exp