INTRODUCTION.

The article introduces a study concerning the illnesses of children from birth to 18 years. The children involved in the study consists of 67 boys and girls who constitute the Maturity Series of the Harvard Longitudinal Studies. The children were followed from birth until they reach their 18th year. Its primary objective is to analyze the children's illnesses experiences in total and by separate categories. The data of the study are reported for both number of illnesses and score of illnesses, as defined for total childhood or those illnesses that occurred from birth to 18 years.