BACKGROUND: The goal of preoperative screening test is to reduce the perioperative morbidity by patients management in case of abnormal test results. But, in view of the low incidence of perioperative complication in otherwise healthy surgical population and cost of routine preoperative screening tests, further examination of their usefulness is required. METHODS: The charts of 1968 patients performed preoperative screening laboratory tests were reviewed to analyse the results of tests retrospectively. The preoperative screening laboratory tests are hemoglobin, platelet count, bleeding time, prothrombin time, partial thromboplastin time, chest X-ray, electrocardiography (ECG), liver function test (LFT), urinalysis, BUN and creatinine. In cases of abnormal results obtained, further studies (pulmonary function test (PFT), arterial blood gas analysis (ABGA), 2D- echocardiography, holter ECG, coronary angiography and abdominal sonography) were analysed. RESULTS: The incidence of abnormal results of total preoperative screening test is 4.5%. The incidence of abnormal results of ECG, chest X-ray, LFT, hemoglobin, and others are 8.3%, 7.8%, 3.7%, 2% and less than 1% in order. For further study, PFT was done in 58 patients, ABGA in 72 patients, 2D-echocardiography in 96 patients, and Holter ECG in 6 patients. CONCLUSION: This study has shown that routine preoperative laboratory screening tests provided little information. Therefore, further studies would be necessary to evaluate the cost-benefit of preoperative screening test compared with the other methods such as history taking and physical examinations that is needed little cost.