The incidence of allergic disease in pediatric outpatient department of a hospital, where primary care is undertaking, was studied from Apr. 1, 1989 to Mar. 32, 1990. The results were as follows, 1) The incidence of respiratory tract disease was the highest with the value of 57.2% of the total patients, followed by gastrointestinal tract disease(13.9%), infectious disease (6.7%), visit for preventive medicine (6.7%), allergic disease (3.0%), neurologic disease (2.9%), cardiovascular disease (2.8%) etc. 2) The allergic patients were 3.0% of total patient and sex ratio was M:F=1.4:1. 3) The allergic patients were most prevalent in1~3 years of age group (46.6%)followed by under 1 year old group (22.4%), and 4~6 years of group (21.3%). 4) The allergic disease was most prevalent in fall (42.8%), followed by spring (20.4%), and winter(19.0%). 5) Among the allergic disease, asthma was most frequent (67.4%), followed by allergic rhinitis(11.8%), atopic dermatitis (10.6%), urticaria (9.3%). 6) Bronchial asthma was most prevalent among 1~3 years of age group (51.9%) and in fall (50.0%) 7) Allergic rhinitis was most frequent among 1~3 years of age group (40.9%) and in fall (34.8%). 8) Atopic dermatitis was most frequent among under 1 year of age group(64.4%)and in spring and winter(28.8%). 9) Urticaria was most frequent among 1~3 years of age group (36.5%) and in summer (32.7%). 10) The percentage of each allergic disease to the total outpatient was as follows; asthma (2.0%), allergic rhinitis(0.40%), atopic dermatitis(0.3%), urticaria (0.3%). 11) Sex ratio of each allergic disease was as follows; asthma (1.5:1), allergic rhinitis(1.6:1), atopic dermatitis (1.1:1), urticaria (1.4:1). With these findings, we ovserved that allergic disease is the fifth most common disease group among the pediatric out patients, covering 3.0% of total patients. Recently, we have had the idea that the prevalence of allergic disease is increasing remarkably. The findings of this study can be used as one of basic data for the study of prvalence and increase of allergic disease with further similar trials afterward.