A simple method to promote the use of human milk and subsequent breast feeding in low birthweight infants was evaluated in 32 babies. In the 'intervention' group (n = 16; mean (SD) weight 1559 (228) g and length of gestation 33.2 (1.8) weeks), infants were allowed to suckle at the breast when their general condition permitted after as much milk as possible had been expressed, and were then given the full required feeds by tube. Full breast feeding was started as soon as the infant could suck adequately. Sixteen control infants (mean (SD) weight 1605 (198) g and length of gestation 34.1 (2.4) weeks), were breast fed in the conventional manner only after it had been established that they could suck well; until then they received all their feeds by tube. After discharge the mean (SD) periods of exclusive and total breast feeding were longer in the group that had received the intervention (3.7 (1.3) and 5.1 (2.2) months, respectively) than among the controls (1.9 (0.6) and 3.3 (1.9) months, respectively). This 'intervention' method helps to promote milk formation, provides sucking experience for low birthweight infants without interfering with their nutritional intake and consequent weight gain, and encourages subsequent breast feeding with its well recognised advantages.