The purpose of this study was to study cross-shift changes of lung function in relation to pesticide use. One hundred and ninety-five male farmers, from a total of 250 farmers, performed lung function tests both pre- and post-shift during high- and low-pesticide-exposure periods. There were no associations between lung function differences across shifts and estimated quantity of pesticides used. However, the cross-shift reduction in forced expiratory volume in 1 second (FEV1; ΔFEV1) was more pronounced during the period when pesticides were used on a larger scale, September 2006, compared with the exposure period with a lower level of pesticide use, April 2007, +50 mL (95% confidence interval [CI]: +24, +76) and +17 mL (95% CI: −13, +48), respectively. This contrast was statistically significant only among the subset of never-smoking participants below 50 years of age. This finding suggests a possible obstructive effect of pesticide exposure on lung function among this rural male population in Palestine. A follow-up of farmers’ lung function in this part of the world along with high-quality measurements of exposure is needed.