End-stage renal disease (ESRD), due to its high morbidity and mortality as well as social and financial implications, is a major public health problem. Outcome depends not only on different modalities of treatment like hemodialysis and peritoneal dialysis, but also on existing co-morbidities, age, duration on dialysis, supportive therapies and infection control strategies. Thus, a detailed study becomes necessary to improve health care delivery, provide medical care and to establish a geographical reference. The present study was undertaken to characterize the ESRD patients by their demographic and co-morbid conditions and relate this to the morbidity and mortality trends. The medical records of 110 ESRD patients seen over a five-year period (June 1995 to December 1999) in two tertiary-care hospitals in Riyadh, Saudi Arabia were studied retrospectively. There were 79 (64.5%) males and 31 (35.5%) females; their age ranged from 17 to 92 years (mean age 53.8 +/- 17.8 years). Diabetes was the commonest cause of ESRD seen in 26 (26.6%) followed by nephrosclerosis, unknown etiology, lupus nephritis, pyelonephritis and primary glomerulonephritis. Diabetes mellitus was the most prevalent co-morbidity seen during the study period and occurred in 65 patients (59%) followed by heart disease in 36 (32.7%), liver disease in 30 (27.3%), cerebrovascular accidents in 13 (11.8%) and neoplasm in 11 (10%). Seven (6.3%) patients only were smokers. Hemodialysis was the most frequent treatment choice as renal replacement therapy. Among the causes of hospitalization, cardiovascular conditions were the leading single cause (19.1%), followed by access related reasons and infections (11.5% each). The overall hospitalization rate was 11.2 days/year. The overall mortality rate was 8.07 deaths/year. The leading cause of death was cardiovascular in 15 (51.7%) followed by unknown/sudden death in eight (27.5%). Other causes of death included fluid overload, gastrointestinal hemorrhage, septicemia, liver disease and pulmonary embolism. Diabetes was the commonest co-morbid cause among the deceased. Old age, diabetes mellitus, prolonged duration on dialysis and cardiac diseases were the common causes of mortality. Our findings are consistent with worldwide reports. The study provides a reference data and will hopefully be helpful in improving the medical care.