This study assessed the relationships of lifetime smoking and initiating smoking with job demands among 2,888 randomly selected workers, aged 15 yr or over, using a post-mailed questionnaire. Cumulated job demands (CJD) was defined as the number of: using pneumatic tools, other vibrating hand tools, hammer, tasks at height, working in adverse climate, pace of working, cold, heat, and noise exposure. Lifetime smoking was reported by 63.8% of subjects, and 5.9% initiated smoking during present job. Logistic model shows that lifetime smoking related to the CJD: OR adjusted for years with job 2.47 (95%CI 1.69-3.60) for CJD> or =4, 1.50 (1.21-1.85) for CJD2-3, and 1.20 (1.00-1.44) for CJD1, vs. CJD0. Initiating smoking also related to the CJD: ORs 3.72 (1.95-7.11), 1.51 (0.96-2.39) and 1.47 (0.97-2.24), respectively. These associations were partly confounded by gender, income, obesity and job. Smoking related to job demands and their limitation should help preventing smoking.