Pre- and post-natal growth was studied from week 17 of pregnancy until 5 years of age in children of women who reported daily smoking at the time of conception, and compared to the growth in children of non-smokers. Fetal abdominal diameter, femur length and biparietal diameter were measured in weeks 17 and 37 of pregnancy, and weight, height and head circumference were measured at birth, and at 6, 13 and 60 months of age in 185 children of smokers and 345 children of non-smokers. Cross sectional data at birth showed that infants of smokers had lower weight and length, but similar ponderal index as infants of non-smokers and this may suggest a symmetrical growth retardation. Longitudinal growth curves indicated that the growth retardation took place in the second half of pregnancy. During the first 5 years of life, children of smokers had complete catch-up growth in weight, a partial catch-up in height, and no catch-up growth in head circumference. At 5 years, children of smokers had a higher ponderal index and skinfold thickness, suggesting that these children, on average, were more obese than children of non-smokers.