Aim of the study: Endotoxins can be deposited on the surface of cotton plants and can be aerosolised during cotton processing. The aim of the study was to investigate the relationship between endotoxin exposure in the cotton textile industry and impairment of lung function. Methods and collective: The employees of a cotton spinning mill (total n = 388) were asked to participate in a cross-sectional study. In total, 182 subjects (47 %) agreed to take part. A random sample of 150 employees was included in the study. All participants were interviewed for demographic data and symptoms of the airways. Lung function analyses were performed. The endotoxin concentration in the air of different work areas was determined in numerous samples. The employees were categorised on the basis of the data into three equally large exposure groups. Results: The current endotoxin exposure in the cotton mill reached levels of 7000 EU/m3, similar to the findings of other studies in the cotton spinning industry. The lung function tests did not show an increase in the frequency of obstructive or restrictive ventilation patterns in this cross-section of workers. However, a significant dose-effect relationship between endotoxin exposure and obstructive ventilation disorders was found. Conclusions: As described in many studies of endotoxins in cotton spinning mills, the results suggest there is a relationship between lung function impairment and endotoxin exposure.