- Asthma is the most common chronic disease amongst children. To find the prevalence of positive allergy skin tests amongst children having asthma attending the asthma clinic in Barzilai Medical Center in Ashkelon Israel. Retrospective study. All medical files of the asthmatic children attending the asthma clinic in Barzilai Medical Center in Ashkelon, Israel, were reviewed. Data regarding their clinical status, past medical history, socioeconomic and familial medical history were collected. One thousand three hundred and fifty three medical files including all the information necessary for the study were reviewed. Amongst the children 1,238 lived in urban areas and towns and 115 lived in rural areas. It was found that most of the children have positive allergy skin tests for house dust mite and mold. Among the urban children 86.2% were found to have positive allergy skin tests for house dust mite compared with 48% of the rural children (P < 0.02). Positive allergy skin tests for mold were found among 63.1% of the urban children compared with 44% of the rural children (p < 0.04). Positive allergy skin tests for most allergens were found to be more prevalent amongst the children living in urban areas compared with the children living in rural areas. The positive allergy skin tess are not related to parental smoking habits or house pets amongst these findings. Most of the children living in the Ashkelon region and positive allergy skin tests for house dust mite. This tendency is more common among the children living in urban areas as compared with children living in rural areas. The reason for this difference has to be studied.