Various reactive dyes can elicit occupational asthma in exposed textile industry workers. To date, there has been no report of occupational asthma caused by the red dye Synozol Red-K 3BS (Red-K). Here, we report a 38-year-old male textile worker with occupational asthma and rhinitis induced by inhalation of Red-K. He showed positive responses to Red-K extract on skin-prick testing and serum specific IgE antibodies to Red-K-human serum albumin conjugate were detected using an enzyme-linked immunosorbent assay. A bronchoprovocation test with Red-K extract resulted in significant bronchoconstriction. These findings suggest that the inhalation of the reactive dye Red-K can induce IgE-mediated occupational asthma and rhinitis in exposed workers.