OSHA surveillance data were collected for 769 individuals employed in four different cotton textile mills. Current workers were asked to complete a questionnaire about personal and family history of atopy or asthma. Both surveillance and survey data were available for 502 individuals. The prevalence of atopy in the population as reported by questionnaire was 18%, while asthma was reported by 4%. Dust levels at the four mills were in compliance with the cotton dust standard during the period of surveillance. No relationship was found between a self-reported history of atopy or asthma and the magnitude or frequency of acute overshift declines in forced expiratory volume during 1 second (FEV1). Nonsmokers had annual changes in FEV1 and forced vital capacity (FVC) comparable to nonexposed populations. In one of the four mills surveyed, annual declines in FEV1 and FVC for current smokers were significantly greater than declines for smokers in the other mills or the general smoking population (p < 0.02). This mill effect was also observed for subjects who were categorized as atopic (p < 0.02). For nonsmokers there appears to be no significant adverse health effect from exposure to the levels of cotton dust observed in these mills.