Diesel exhaust (DE) has been accused for various health outcomes including exacerbation of asthma, chronic bronchitis. Exposure to DE has long-term effects on lung development in children and reductions in lung function have been reported. The aim of the study was to evaluate the annual changes in forced expiratory flows among toll collectors in Duzce city from 2002 to 2005. Annual FVC, FEV1 and MMF changes in smoker and nonsmoker 58 toll collectors and 37 controls selected among men who worked in the same company as officer have been followed up. No significant changes were seen in expiratory flows among smoker-nonsmoker toll collectors and controls (p>0.05). Annual FVC, FEV1 and MMF changes were not significantly different between smoker and nonsmoker toll collectors. Twelve toll collectors (20.7%) in the study group and 4 (10.8%) controls were found to have FEV1 and FVC below longitudinal lower limit of normal. The difference between groups did not reach statistically significance (p>0.05). Toll collectors (18/58) and controls (15/37) with spirometric measurements for three times showed no difference according to the rate of annual difference in either FEV1 (-21.3 +/- 133.1 ml/yr vs -44.3 +/- 166.6 (ml/yr) or FVC (13.2 +/- 202.9 ml/yr vs. -16.1 +/- 204.2 ml/yr). Further investigations including large groups with long term follow up are needed to observe annual FVC, FEV1 and MMF changes among toll collectors.