We determined the duration of breast-feeding for 362 full-term infants of middle- and upper-class mothers. The median duration of breast-feeding was five months for infants whose mothers elected to postpone physical contact (n = 94), four months for infants whose mothers elected early physical contact but later suckling (n = 82), and 8.5 months for infants whose mothers elected to suckle during early contact (n = 186). The rate of decline of breast-feeding was significantly slower for infants who were suckled early than for those who were first suckled later. The association between early suckling and prolonged breast-feeding was not affected by the infant's gender or maternal parity.