Summary. Growth of macrosomic newborns (birth weight 4000 grams and more) and control group newborns (birth weight from 2500 to 3999 grams) in the course of their first year of life has been compared. Although the absolute growth in weight and length is higher in macrosomic boys and girls, the relativity in their growth in the course of the first year of their life is higher among the control group infants. Boys from the control group have increased their birth weight for 203%, while macrosomic infants for 177% (control group girls 196% against macrosomic 159%). The relative difference in weight between the groups of macrosomic and control group boys decreased from 26% (at delivery) to 14% in the course of their first year of life, and in girls from 23% to 8%. Control group boys have increased their birth length for 53%, while macrosomic for 49% (girls: control group 52% against macrosomic 47%). The observed tendency to decrease the difference in antropometric characteristics between the macrosomic and control groups of newborn children of both sexes, probably may be explained by the weakening of the influence of prenatal factors which have resulted in macrosomy and strengthening of the influences of postnatal factors (socio-economic) by which the groups didn’t differ significantly.