Background: occupational exposure to pesticides produces health disorders for exposed individuals by inhalation, skin contact, or ingestion. Aim: to study the spirometric changes in relationship to serum cholinestrase level among a group of workers employed in a pesticides processing factory. Subjects and methods: Fifty six pesticide-exposed males and 56 non-exposed male workers (as a control group) were chosen for this study. Each participant was subjected to a questionnaire including personal data; medical examination; serum cholinestrase level; and spirometric measurements (FVC%, FEV1%, FEV1/ FVC% & FEF75-85 %). Results : the respiratory manifestations as cough, expectoration, dyspnea, wheezes and crepitations were significantly more prevalent among pesticide-exposed workers than controls. Significant decrease in the serum cholinestrase level and in mean values of spirometric measurements for FVC%, FEV1%, FEV1/ FVC% & FEF75-85 % were found among pesticide-exposed workers than the control group. The decrease in studied spirometric mean values among pesticide-exposed workers was associated with increased length of duration of work. Also, there was a significant positive correlation between mean values of serum cholinestrase (ChE) among exposed workers and studied spiromet-