BACKGROUND: The relationship between Socioeconomic status(SES) and mortality, commonly studied in the developed countries but not in the less developed countries, was evaluated in a cohort of 759,665 Korean male public servants aged 30-64. METHODS: Data on the biological and social characteristics, SES defined as the grade of monthly salary were obtained from the Korea Medical Insurance Corporation. Vital status of the study subjects was followed-up from 1992 to 1996 through the dataset of the Korea National Statistical Office. The risk of ortality associated with SES was estimated using Cow proportional hazard model. RESULTS: There were total 13,330 deaths during the five-year follow-up period. Lowest-SES group had significantly increased risk of all-cause mortality compared to the highest-SES group(Relative risk [RR]: 1.52). Mortality from cancer(RR=1.19) and cerebrovascular disease(RR=1.58) were also significantly increased in the lowest SES group. Mortality from ischemic heart desease, however, had no relationship with SES. CONCLUSIONS: Socioeconomic differentials in mortality were reconfirmed in Korean men. The differences in the relationship between mortality and SES according to the specific cause of death suggest that SES influence health through the various pathways.