Average number of sick leave hours per month taken by smoking and nonsmoking employees of Missouri's Department of Health were examined. During a 20-month period 97 smokers took 5.3 hours per month sick leave, whereas 309 non-smokers took 4.3 hours, a 23% difference. Excess sick leave was taken by smokers regardless of their sex, marital status, or age group. Smokers who were male, unmarried, or older took 22% to 38% more sick leave than their nonsmoking counterparts. It was estimated that for excess sick leave only, the smokers cost the department $11,931 per year. Using total cost figures developed by Weiss yielded an estimated excess cost of $510,802 per year.