An increase in allergic diseases in Western societies has been observed in all epidemiological studies. Various risk factors have been invoked to explain this increase, but the results are still inconclusive. We examined the type of patients who visited a hospital pediatric allergology unit in terms of the type of pathology presented, environmental factors, and time from the onset of symptoms until referral for allergy study. We evaluated 200 children ranging in age from 1 month to 15 years who were distributed by pathology: 119 referrals for respiratory manifestations (asthma, rhinitis, coughing, ...), 46 for food-related pathology, and 35 for adverse reactions attributed to medications. Among the risk factors, 69% of the children had a family history, 63.5% were exposed to smoking, and all of the patients were from urban and urban-industrial areas. We found no relation between the type of pathology and birth month. The natural history of allergic disease showed the following sequence: food allergy--respiratory allergy--medication allergy. In every case there was an important delay in diagnosis. The patients who visited our department soonest were infants (for presumptive allergy to cow milk protein or suspected adverse reaction to medications). It is evident that in recent years we are seeing a major increase in allergic diseases, particularly in industrialized countries. From a clinical point of view, manifestations such as asthma, rhinitis, and atopic dermatitis are increasing, which all working groups attribute to an increase in the prevalence of allergy. Epidemiological studies of large population samples use non-standard methods, with different selection criteria, ethnic breakdown and geographic differences. This makes it difficult to compare available data. Therefore, we think that it would be advisable if epidemiological studies would attempt to follow a model, which would facilitate the comparison of studies. Our aim was to evaluate the type of patients who required allergy studies in relation to the pathologies that they present and the different diagnostic methods to determine the presence of false allergies or non-allergies, the delay until study, most frequent pathologies, and environment. We report the data obtained from a sample of 200 children who visited our department for the first time in the period of a natural year.