The effect of hand hygiene was measured by hand culture before and after hand hygiene for 86 nurses, doctors, and nurses aide/housekeepers in Surgical Intensive Care Unit. The subjects were asked to press their dominant hand in hand-shaped Mannitol salt agar immediately after patient contact and then washed their hand by preferred hand hygiene agents [soap and water, waterless alcohol gel, or 4% chlorhexidine gluconate detergent(CHG)], and cultured one hand again. Amount of isolated microorganism was calculated by counting the number of divided areas(1 × 1cm) which is culture positive in hand culture plate. The amount of microorganisms were significantly reduced from 58.1(±38.59) to 27.4(±30.4) cells after hand hygiene. The staff nurse's hand hygiene was more effective compared to medical doctors and nurses aide/housekeepers. Methicillin-resistant Staphylococcus aureus(MRSA) was isolated in 41(47.1%) subjects ; but only removed 100% in 28(32.2%) subjects. When the amount of hand microorganisms was compared by subject's preferred hand hygiene agents, it was decreased in order of 4% CHG, waterless alcohol solution, soap and water, and water. The hand hygiene practice was inadequate to reduce hand microorganisms and significantly different by occupations. Further research and development of hand hygiene improvement program which emphasize the quality of hand hygiene is recommended.