Aim: The aims were to investigate the prevalence of breastfeeding after conception with assisted reproductive technology (ART) and identify risk factors for breastfeeding duration <6 weeks and cessation of breastfeeding before the baby is 8 months old. Methods: A consecutive cohort of women who had conceived at one of two ART centres in Melbourne, Australia, was recruited in early pregnancy. The women completed telephone interviews and postal questionnaires in pregnancy and 3, 8 and 18 months after the birth. Results: Of 239 eligible women, 183 (77%) agreed to take part. Participants were more likely than the general population of childbearing Australian women to initiate breastfeeding (89% vs 83.3%, p = 0.05) but by 3 months, a smaller proportion was breastfeeding exclusively (46% vs 57.3%, p = 0.004). The proportions not providing any breast milk at 6 weeks and 8 months were 23% and 57%, respectively. More anxiety in late pregnancy and sub-optimal breastfeeding advice predicted breastfeeding duration <6 weeks and breastfeeding cessation before 8 months. Conclusion: The predictors of less favourable breastfeeding outcomes after ART identified may be modifiable. Antenatal strategies to reduce anxiety in pregnancy and postnatal strategies to ensure consistent breastfeeding advice may improve breastfeeding outcomes among women who give birth after ART.