Species of the Cupressaceae family are an important cause of respiratory allergies in countries with a Mediterranean climate. An allergenic extract from Cupressus arizonica pollen was prepared with two extraction steps followed by ammonium sulfate precipitation, giving a protein yield of about 3%. Cupressus arizonica pollen extract was also characterized by means of sodium dodecylsulfate-polyacrylamide gel electrophoresis, followed by IgE and IgG immunoblotting and lectin blotting. IgE reactivity was restricted to six components, whereas IgG binding showed a more complex pattern. A 43 kd component, predominant both in its intensity and frequency of recognition by human IgE antibodies, was identified as the major allergen of C. arizonica. Four of the six IgE-binding components, including the major allergen, seem to be glycoproteins, as confirmed by the lectin blotting analysis. The extract produced inhouse was used to set up an immunoenzymatic test to evaluate the specific IgE binding in a panel of sera from 33 immunotherapy-free subjects who were monosensitized to cypress pollen. The percent of positivity obtained was much higher than that reported in the literature for commercial immunoassays.