To investigate the duration of breastfeeding and the impact of maternal factors for cessation of breastfeeding in twin infants, the authors undertook a population-based cohort study. Breastfeeding data obtained from Child Health Centres were matched with data on infant and maternal demographics from Swedish national registers. A total of 1.657 twins were included, of whom 695 were born preterm. Breastfeeding frequencies in preterm twins were 79% at 2 months, 58% at 4 months, 39% at 6 months, 14% at 9 months, and 6% at 12 months. In term twins, the corresponding frequencies were 84%, 63%, 45%, 18%, and 6%, respectively. In both preterm and term mothers, mothers who had a lower educational level or smoked at first antenatal care visit were subject to earlier cessation of breastfeeding by 6 months of age. In addition, in mothers of term infants, mothers who were < 23 years old or primiparous had a higher risk for cessation of breastfeeding before 6 months. Thus, mothers of twins have a good potential to breastfeed, but additional support is needed for those more susceptible to early cessation of breastfeeding.