A describe was presented of airborne endotoxin concentrations in various areas within a large cotton mill in Managua, Nicaragua, Central America. The mill employed about 1300 workers in several facilities. Samples of elutriated dust were obtained. The samples were taken from the textile yarn preparation area, the weaving area, and a bale storage warehouse. Mean dust levels in the mill ranged from 0.10mg/m3 in the storage warehouse to 1.73mg/m3 in the opening area. Contamination of the air with endotoxins in the vertical elutriator dust was lowest in the warehouse area where no mechanical processing was occurring, and highest in the opening area, 9 to 3138 endotoxin units/cubic meter. A gradual decrease was noted in endotoxin contamination from the opening to spinning areas of yarn contamination. The elutriated dust endotoxin correlation was relatively high, with a coefficient of variation of 50% when examined in a linear regression model. The authors suggest that cottons grown and processed in tropical climates do not necessarily have higher levels of contamination by gram negative bacteria and the cottons are still relatively rich in readily aerosolized endotoxin.