The association between serum lipids and mortality has not previously been established in Thailand. Baseline data from the Electricity Generating Authority of Thailand (EGAT) cohort study, plus a resurvey of the cohort 15 years later were analyzed. Participants were employees of EGAT: 2,702 men and 797 women. Total cholesterol (TC), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), and triglycerides (TG) were taken as predictive variables; age, sex, hypertension, diabetes, cigarette smoking, alcohol drinking, and body mass index were taken as confounders. Dependent variables were all-causes and specific causes of mortality over 17 years of follow-up. The major cause of death among men was cardiovascular disease (CVD); among women, it was cancer. Relative risks (RR) for specific causes of death, for a mmol/L increase in each lipid, were estimated after adjustment for confounding factors using Cox proportional hazards regression. TC and LDL-C were negatively associated with liver cirrhosis mortality, although it was likely that the low cholesterol concentration was a consequence of the disease. HDL-C was negatively associated with CVD mortality (RR = 0.59; 95% confidence interval [CI], 0.39-0.93), coronary heart disease (CHD) mortality (RR = 0.36; 95% CI, 0.17-0.75) and all cause-mortality (RR = 0.68; 95% CI, 0.54-0.87). TG was not associated with mortality. HDL-C is an important risk factor for CVD in middle-class urban Thais. Health promotion programs to improve lipid profiles, such as effective exercise campaigns and dietary advice, are required to increase HDL-C and to help prevent CVD and premature death in Thailand.