This study was performed to ascertain the degree to which the care of hospitalized diabetic and hypertensive patients conforms to published guidelines for the detection and management of early renal disease. It was designed as a retrospective chart audit. Six hospitals, four nonurban referral centers, and two urban teaching institutions provided the data. Patients were a random sample of Medicare beneficiaries, with a mean age (SD) of 65.6 (9.1) years, admitted during 1994 with a primary or secondary diagnosis of either diabetes (n = 260) or hypertension (n = 327). A urinalysis was obtained for 163 (62.7%) of the diabetic patients. Among diabetics who had their urine tested, 31.3% had 1+ or greater dipstick proteinuria. A serum creatinine was obtained for 298 (91%) of the hypertensive patients, and 11.8% had a value of 1.5 mg/dL or greater. Abnormal renal function tests were recorded in the discharge summaries of 7.8% of the diabetic and 11.4% of the hypertensive patients. Patients with abnormal renal function were no more likely to be treated with angiotensin-converting enzyme inhibitors (ACEIs). Nonsteroidal antiinflammatory drugs (NSAIDs) were prescribed for 6% of diabetic and 8.8% of hypertensive patients with abnormal renal function at discharge. Despite the high prevalence of renal functional abnormalities detected by routine laboratory tests administered to elderly hospitalized diabetic and hypertensive patients, the medical records of these patients did not document awareness or appropriate management of the potential underlying kidney disease.