BACKGROUND: There are few preoperative assessments focused on elderly surgical patients in Korea. Current study suggest that preoperative tests should be ordered only when the history or finding on physical examination have indicated for test. We performed a study to evaluate the preoperative assessment and to determine the need for routine preoperative laboratory test in elderly patients. METHODS: Three hundred forty-five patients aged 65 yrs or older presenting for elective surgery requiring general or regional anesthesia were divided into three groups according to age. Data was obtained from chart review and anesthesia preoperative records. Demographic information included age, sex, body mass index, coexisting disease, type of surgery and ASA classification. Clinically obtained preoperative laboratory test results (hemoglobin, platelet, chest X-ray, ECG, BUN, creatinine, ALT, AST, arterial blood gas analysis, pulmonary function test, PT, PTT, echocardiography) were measured. RESULTS: Fifty-seven percent were women. The most frequently performed procedures were general surgery followed by orthopedic surgery. In 345 patients, 47.5% of the patients had a coexisting disease. The most frequently coexisting disease was hypertension. 78.6% of the patients were classified as ASA class 2 and 3. The abnormal findings on ECG, pulmonary function test, and chest X-ray were 46.4%, 48.3%, and 42.6% respectively. 48 patients without any clinical history and symptoms had abnormalities on the routine laboratory test. CONCLUSIONS: We demonstrated that 47.5% of the patients had a coexisting disease and the majority of the patients were classified as ASA class 2 and 3. Changes in the cardiovascular and respiratory function were greater than other functions. We concluded that routine preoperative laboratory test in elderly is useful as a part of preoperative assessment.