The aim of our study was to identify the factors influencing smoking behaviour in a population of workers. To this end, we conducted a cross-sectional study among employees of a water distribution company in Sfax, Tunisia. The data collected related to socio-professional characteristics, smoking behaviour and assessment of occupational stress using the Siegrist questionnaire. Seventy-one employees took part in the survey. An effort/reward imbalance was found in 35.2% of employees. The proportion of smokers was 62%. Strong tobacco dependency was noted in 31.8% of smokers. Smoking was associated with active work and the presence of an effort/reward imbalance. Tobacco dependence was associated only with the presence of an effort/reward imbalance. Our results suggest that reducing stress at work by ensuring a better balance between efforts made and rewards obtained could prevent smoking.