The purpose of this paper is to present the changes in growth patterns in different socio-economic classes of Zagreb school children over the period 1973-1991. Classes are defined by parental occupation. Surveys were performed in 1973, 1982 and 1991 covering 8938, 10700, and 7400 examinees aged 7 to 19 respectively. In all three observed generations boys and girls belonging to social group I (nonmanual workers' families) were taller than their peers in group III (manual workers' families). Differences were most pronounced in 1973. Mean height of children from 'mixed' families (class II) were mostly between two other groups. Positive secular changes in both genders were most pronounced in children belonging to manual workers' families--girls observed in 1991 being 2-4cm and boys 2-6cm taller than their peers in 1973. In children from nonmanual workers' families the secular increase was small in younger age groups--in boys up to 11 hardly noticeable, while in both genders from the age of 13 on, the mean height increase reached or even surpassed that observed in manual workers' children. Positive changes in all observed groups were more pronounced in the period 1973-1982 than in 1982-1991. Mean weight changes, in general over period 1973-1991 corresponded to changes in height. However, the average weight gain in girls in class I was somewhat lower compared to the gain in height, particularly in older age groups. In the same period, 19731991 the mean menarcheal age in girls showed the reversed trend i.e. a shift towards the older age. In class I the reversal was noticed in the first period, parallel to intensive height increase, while in class III positive changes in height were accompanied by significant lowering of menarcheal age. In this group the reversal was observed in the second period 1982-1991.