Because the pediatric age represents a good model to study the correlation between the exposure to allergens and development of respiratory allergy, we investigated the occurrence of a perennial type of symptomatology in children monosensitized to Olea europaea (O.e.) pollen allergens compared with subjects with monosensitization to Parietaria (P) and Gramineae (G) in order to confirm our previous observations in adults. We selected a group of 52 children with rhinitis and/or bronchial asthma and a SPT positivity only to pollens (30 to P, 15 to G, and 7 to O.e.). Using commercially available allergenic extracts and reagents, the following diagnostic procedures were performed: skin prick test (SPT), specific IgE assays (RAST), nonspecific bronchial provocation test (NsBPT) and specific nasal provocation test (sNPT), respectively, in patients with bronchial asthma and rhinitis. Pollen counts and a statistical analysis using Spearman's correlation test were also carried out. Six of seven children with monosensitization to O.e. allergens showed a perennial pattern of symptoms in comparison to 7 of 23 and 3 of 12, respectively, in subjects with P and G pollinosis. All patients with perennial nasal symptoms of O.e. group exhibited a late nasal response after sNPT. Although these findings on nasal response may partially explain the occurrence of a prolonged inflammation of the nose induced by O.e. allergens, we think that other possibilities could be investigated. In our opinion, further studies are necessary using better purified and standardized diagnostic materials and, moreover, a greater number of O.e. monosensitized children living in other geographical areas need to be examined for a comparison of our results with theirs.