This is a follow-up study during one year of a random sample of 468 children younger than 6 attending an outpatient clinic of the North Metropolitan Health Service. The objective was to study the frequency of episodes and consultation and to describe the diagnosis by age and month. 53% were male, 29.1% less than one year and 8.2% aged 5. They had 2 498 episodes and 3 122 consultations during the 12 month period, corresponding to 5.3 episodes and 6.7 consultations per child per year. Of the diagnosis the most frequent are respiratory illness 67.1%, infective and parasitic causes 10.2%, nervous system (including eyes) 9.2%, dermatological, digestive and accidents each representing 2%. Individual affections of importance were acute bronchitis 17.3%, obstructive bronchitis 16.9%, pneumonia 6.2%, acute otitis 6.4%, tonsilitis 5%, diarrhea 5%. Diarrhea, dermatological diseases and conjunctivitis are more frequent in spring and summer. Respiratory illnesses are more frequent between april and august. There were no differences with respect to sex or age.