To determine the quantity, variability, and mean aerodynamic diameter of latex aeroallergens in a large medical center, we collected air samples from work sites by using area and personal breathing zone air samplers, and we measured latex allergens by an inhibition assay with IgE antibodies from latex-sensitive individuals. Latex aeroallergen concentrations in 11 areas where powdered latex gloves were frequently used ranged from 13 to 208 ng/m3, and in areas where powdered latex gloves were never or seldom used, concentrations ranged from 0.3 to 1.8 ng/m3. Installation and use of a laminar flow glove changing station in one work area did not reduce latex aeroallergen levels. Large quantities of allergen were recovered from used laboratory coats and anesthesia scrub suits and from laboratory surfaces. Latex allergen concentrations in personal breathing zone samplers worn by health care workers in areas where powdered gloves were frequently used ranged from 8 to 974 ng/m3. Exposure likely occurs when gloves are changed and as a result of resuspension from reservoirs of powder in the room and clothing. Latex allergens were found in all particle sizes but were predominant in particles greater than 7 microns in mass median aerodynamic diameter. Results of electrophoretic immunoblotting showed that the aeroallergens are primarily the higher molecular mass components of the latex glove proteins. Measures to control exposure can be monitored by both area and personal air sampling with this immunochemical approach. Use of gloves with low allergen content or powder-free gloves appears to be more effective than use of a laminar flow glove changing station in reducing aeroallergen levels.