There is good evidence that lactational amenorrhea (LAM) is an effective method of fertility regulation during the first 6 months postpartum, provided no other food is given to the baby and the mother remains amenorrheic. However, although breast-feeding is strongly promoted in many maternity hospitals that also run postpartum family planning programs, LAM is rarely included among the contraceptive options being offered. This paper presents the results of an operational study which compared the prevalence of contraceptive use and the cumulative pregnancy rate at 12-months postpartum among 350 women observed before and 348 women studied after introducing LAM as an alternative contraceptive option offered to women following delivery at the Instituto Materno Infantil de Pernambuco (IMIP), in Recife, Brazil. The percentage of women not using any contraceptive method was significantly lower (p<0.0001) after the intervention (7.4%) than before (17.7%). This difference remained statistically significant after controlling for age, number of living children, marital status and years of schooling. The proportion pregnant one year postpartum was also significantly lower (p<0.0001) after the introduction of LAM (7.4%) than before (14.3%), but the difference was no longer significant after controlling for the same variables. It is concluded that LAM is a useful addition to family planning postpartum programs.