Objective : Several studies hove suggested that reduction of cholesterol concentration and low cholesterol level increases suicide, homicide, and depression. The authors sought to determine whether low cholesterol is associated with a history of suicidal attempts among major depression patients. Method : The subjects were 105 patients with major depression, diagnosed according to the DSM-III-R criteria, and 105 age, sex matched healthy controls. Blood was token following overnight fast and serum cholesterol concentration were measured by a enzymatic method Results : The serum cholesterol level was significantly lower in the patients with major depression than in healthy controls($180.4{pm}43.4mg/dl$ vs $199.7{pm}35.8mg/dl$). And the serum cholesterol level was significantly lower in major depression patients with suicidal attempt than in major depression patients without suicidal attempt($156.7{pm}38.2mg/dl$ vs $ 187.8{pm}42.5mg/dl$) Conclusion : It is hypothesized that low cholesterol level is associated with depression by modifying the serotonin metabolism and the production of interleukin-2, low cholesterol concentration should be further investigated as a potential biological marker of suicidal risk in major depression. Prospective study with serial cholesterol determinations should be done.