INTRODUCTION: Allergy skin tests are an important tool in the diagnosis of allergy diseases. They are useful in epidemiologic studies. OBJECTIVES: The aim of our study is to estimate the prevalence of the skin sensitivity in a sample of unselected population and to study the relationship between skin test reactivity and clinical manifestations. PATIENTS AND METHODS: During 9 months, we undertake skin prick-test in 500 subjects. Our population was recruited in the blood sample room of the biochemistry laboratory of the University Hospital of Sousse. Seven aeroallergen was tested: Dermatophagoïdes pteronyssinus (DPT), Dermatophagoïdes farinae (DF), Pollens of Graminees, Olive-tree, Partetaure, Cockroach and Candidine. A positive and a negative control tests were made. RESULTS: 34% of the population was sensitized to one or more aeroallergens. In the litterature this prevalence vary from 9 to 55.5% according to the methodology applied. In our study the skin reactivity does not change with sex (p = 0.26) but was high in subjects aged between 15 and 35 years. 21.8% were sensitized to house dust mites (DPT, DF) and 18.2% to pollens (Olive-tree, Graminees, Parietaire). Skin reactivity was more common when subjects had personal atopic history (p < 0.003) and/or had actual allergic symptoms particularyrhinitis and asthma (p < 0.006). CONCLUSION: Skin reactivity to common aeroallergens is frequent in the general population, particularly in symptomatic subjects affected by rhinitis and/or allergic asthma. This skin sensitization is the result of genetic and environmental interaction, but skin sensitization does not mean allergy.