A 7-yr study was conducted to evaluate the respiratory effects of fluorine compounds on exposed workers in a small-scale enamel enterprise. Air monitoring was done and 75 pairs, exposed and non-exposed workers were examined. The applied tests were: an epidemiological questionnaire, the bronchitis record, clinical examinations and urinary fluorine. Linear regression analysis was done. The values of fluorine in the air of workplaces ranged from 0.1 to 3.7 mg/m3 air during the study. Twenty five point and seven percent of exposed workers presented chronic rhinitis, laryngotracheitis and bronchitis. The smoking habit was similar in both groups. The incidence of chronic bronchitis was significantly higher in exposed workers compared to the non-exposed ones. The values of urinary fluorine were higher in the exposed versus the control group. Linear regression analysis has shown positive correlations between the fluorine exposure and incidence of chronic bronchitis (r=0.75), as well as the incidence of chronic respiratory diseases (r=0.71). Fluorine exposure may be responsible for the high incidence of chronic irritative respiratory diseases, especially for chronic bronchitis in exposed workers. For diseases prevention it is advisable to reduce the levels of fluorine in the air of workplaces and to decrease the concentration of fluorine compounds in the composition of enamel.