The relationship between pet ownership and respiratory allergy and symptoms was investigated in a population of 3344 Dutch children of 6-12 years old. Pet ownership was defined by the presence of cats, dogs, birds and/or rodents in the home. The reported prevalence of respiratory allergy and symptoms was lower among children of current pet owners than among children of parents who owned no pets. When past pet ownership was taken into account, however, a different picture emerged. The lowest prevalence of respiratory allergy and symptoms was found in children of current pet owners who had no pets in the past. The next lowest prevalence was found in children of current pet owners who had had pets in the past also. The next highest prevalence was found in children who never had pets in their life. The highest prevalence of reported pet allergy, chronic cough, wheeze, attacks of shortness of breath with wheezing, and doctor-diagnosed asthma was found in children who had pets in the past but not anymore. Past cat ownership especially was associated with a high prevalence of pet allergy and doctor-diagnosed asthma. Almost 2% of the population reported to never have owned pets for health reasons, and more than 12% reported removing pets from the home for health reasons in the past. These results show that selective avoidance and removal of pets leads to distortions of cross-sectional associations between pet ownership and respiratory allergy and disease among children.