Cigarette smoker and non smoker mothers from Africa, Chile, were followed along pregnancy and lactation and the influence of cigarette smoking on infant's birth weight and length of lactation was assessed from a sample of 240 pregnant women, 87 (36.3%) of them were actively smoking mothers and 33 among these (37.9%) smoked throughout all pregnancy and lactation. Mothers who smoked along lactation showed significantly shorter exclusive breast feeding time (2.6 month) in comparison with non smokers (3.5 month, p < 0.05) and their total lactation time was also reduced (4.2 vs. 5.3 months respectively, p < 0.01).