Chloramine-T is a small molecular oxidizing agent that has been widely used as a disinfectant since the beginning of this century. It is generally used in a 5% solution but it is also supplied in powder form. Sporadic case reports of immediate-type sensitization to this agent associated with symptoms of asthma, rhinitis and urticaria have appeared during recent decades. In one of the reports, specific IgE antibodies in sera of four patients who developed asthmatic symptoms after exposure to chloramine-T were demonstrated using a radioimmuno-assay. Three cases of bronchial asthma in workers who had handled chloramine-T powder are described in the present report. Positive skin-prick test reactions to chloramine-T were observed and specific IgE antibodies to human serum albumin treated with chloramine-T were detected using the classic radioallergosorbent (RAST) technique in all three patients.