Abstract. This paper highlights a clinical case of a patient suffering bronchial asthma and rhinoconjunctivitis due to sensitization to Tetranychus urticae(TU), commonly known as the red spider mite, which belongs to the Prostigmata sub-order of the Tetranychidae family, in relation to a work environment (a carnation nursery). Both prick and intradermal skin tests were positive, as well as specific bronchial challenge tests with TU extract. Specific IgE was demonstrated by RAST (Class 3). Unspecific bronchial provocation with methacholine was negative. Sodium dodecylsulfate-polyacrylamide gel elcctrophoresis (SDS-PAGE) immunoblotting revealed the presence of seven main IgE binding proteins, the more intense bands being those appearing at 21. 17 and 15 kDa. This indicates a case of immediated type hypersensitivity to Tetranychus urticae with a clear correlation to occupational environment.