Allergic sensitization to workplace allergens can result in occupational asthma (OA), rhinitis, and dermatoses. Occupational asthma, accounting for 2% to 15% of all new cases of asthma, is caused by more than 240 reactive chemicals or natural proteins. Diisocyanates, used in urethane production and spray painting, are the leading causes of OA. Occupational asthma must be objectively confirmed by demonstrating significant decreases in lung function associated with exposure to a causative agent. An early diagnosis of OA followed by elimination of exposure to a causative agent may be curative and prevent progression to chronic asthma. In the last decade, protein allergens in natural rubber latex gloves have emerged as the leading cause of work-related cutaneous and respiratory allergic disorders in health care workers. In the workplace, occupational allergic contact dermatitis is almost always caused by chemicals, including nickel, chromates, and epoxy resins, whereas contact urticarial reactions are most often due to protein allergens. The primary treatment of occupational allergic disorders is strict avoidance of exposure to the inciting agent.