Tetranychus urticae is a macroscopic mite known as "red spider mite". It is a cosmopolitan and polyphagous mite which parasitizes both fruit trees and herbaceous plants, particularly in greenhouses. Contribution of T. urticae to occupational asthma among greenhouse workers has been studied to identify and describe the main T. urticae allergens. In this study we described and compared the physiochemical characteristics of the main. T. urticae allergens from three different sources, carnation, cucumber and vegetable marrow. Forty-two green-house workers with occupational T. urticae allergy were included. Extracts were prepared from mite bodies collected from the three different sources; skin prick tests, specific IgE, SDS-PAGE and SDS-PAGE immunoblotting were carried out with the three T. urticae extracts. Cross-reactivity was measured by RAST inhibition. These assays were done with each of the three extracts in solid and fluid phases. All patients showed a positive prick test to T. urticae extracts from carnation, 39 (93%) to those from cucumber, and 34 (81%) to those from vegetable marrow. Specific IgE was positive in 80% of patient sera from T. urticae extract from carnation, 58% and 63% in that from cucumber and vegetable marrow, respectively. SDS-PAGE immunoblotting of the extracts showed coincident and relevant allergens. The similar curve obtained by RAST inhibition assays revealed the high epitope similarity from the three extracts. In conclusion, T. urticae extracts from parasitic carnation, cucumber and vegetable marrow cultures showed a high epitope similarity with three relevant allergens with molecular mass of 25, 19 and 15 to 17 kDa.