Hemoglobins of the Diptera (insect) family Chironomidae have been identified as causative allergens in asthmatic patients. In this study, 229 Japanese, 17 Taiwanese, and 92 Swedish sera from atopic patients were tested for antibodies againstChi tI, the hemoglobin from the European midge speciesChironomus thummi, and against crude extracts from the Japanese midgesTokunagayusurika akamusi (T. akamusi)andCricotopus sylvestris (Cr. sylvestris).Nearly 40% of patients showed a positive reaction toCr. sylvestrisextract, which contains no hemoglobin. This result is probably due to the presence of other partially cross‐reacting allergens than hemoglobin. Nearly all tested Japanese serum samples showed cross‐reactivity betweenChi tI andCr. sylvestris, a finding which is evidence for common epitopes in both midge species. Furthermore, an overall good correlation between the amounts of IgE antibodies againstChi II andChi 1I component III was found in sera from Swedish, Japanese, and German patie