Laboratory animal allergy (LAA) is a significant occupational hazard for workers in a number of research settings, including the pharmaceutical industry. Prevention of allergy and asthma is important because the illness can affect health and career. In a major pharmaceutical company, in an effort to prevent LAA, a comprehensive program to reduce exposure to environmental allergens was developed. The program included education, engineering controls, administrative controls, use of personal protective equipment, and medical surveillance. A prospective survey of five years of data was completed to determine the effect of the program on the prevalence and incidence of LAA. After instituting this program, we found that the prevalence of LAA ranged from 12%-22% and that the incidence was reduced to zero during the last two years of observation. We concluded that LAA is preventable through the implementation of a comprehensive effort to reduce exposure to allergens.