Asthma, allergic rhinitis and idiosyncrasy to aspirin stand for an increasing epidemiologic. In Poland an epidemiological study has been carried out in 11 centres, showing the occurrence of asthma at 5.4% of general population, for allergic rhinitis and idiosyncrasy – 8.5% and 0.5%, respectively. Some publications suggest more often presentation of idiosyncrasy in atopic patients. Taking under consideration high and increasing occurrence of allergy and massive use of non-steroid anti inflammatory drugs, their coincidence is quite important and we decided to investigate it. In a retrospective analysis of patients diagnosed at the Department of Internal Medicine and Allergology, Wrocław Medical University, we determined a group of 1 557 patients suffering from at least of one of these conditions. Asthma has been recognized in 1 015 patients (65%), allergic rhinitis and aspirin idiosyncrasy in 495 (32%) and 363 (23%), respectively. Coincidence of asthma and allergic rhinitis has been reported in 255 patients, and coincidence of asthma or rhinitis and idiosyncrasy – in 3% and 6%, respectively. We conclude that asthma and allergic rhinitis coexist very frequently, confirming a mutual pathophysiologic background and the concept of united airways disease. Further, idiosyncrasy appears 10 times more often in allergic patients than in general population.