BACKGROUND: Pinus pollen allergy has been generally considered to be rare and clinically insignificant. In our geographical area, Pinus pollen constitutes one of the most predominant pollen together with Poaceae and Urticaceae pollen. Pinus pinaster and Pinus radiata are the main species. OBJECTIVE: This work aimed to determine the atmospheric fluctuations and the existence of patients monosensitized to Pinus pollen in our region. METHODS: Patients attending our outpatient clinic in the last 4 years with positive cutaneous tests to Pinus pollen and with respiratory symptoms were selected. They were skin tested with commercial extracts of a battery of inhalants including Pinus pollen. Serologic specific IgE to Pinus pollen was performed by CAP system (Pharmacia & Upjohn, Uppsala, Sweden). Airborne Pinus pollen counts in our city were obtained for a 5-year period (1995 to 1999). RESULTS: We present 10 patients with sensitivity to Pinus pollen and with symptomatology coinciding with Pinus pollen season (February to April). Most of these patients were monosensitizated to Pinus pollen and suffered from seasonal rhinoconjunctivitis. Pinus pollen is present in our area in large amounts from February to April with a peak pollen count in March and April. CONCLUSIONS: Pinus pollen may be an important allergen since by itself can be the only cause of allergic disease. Therefore, we think that it must be taken into account in patients living in areas with high Pinus pollen concentrations and with seasonal respiratory disease.