Objective Previous studies have assessed breastfeeding-support programmes. Among these, osteopathic manipulative treatment (OMT) is a frequently used approach, although without strong evidence of efficacy. Methods A double-blind randomised controlled trial was conducted between July 2013 and March 2016. Breastfed term infants were eligible if one of the following criteria was met: suboptimal breastfeeding behaviour, maternal cracked nipples or maternal pain. The infants were randomly assigned to the intervention or the control group. The intervention consisted of two sessions of early OMT, while in the control group, the manipulations were performed on a doll behind a screen. The primary outcome was the exclusive breastfeeding rate at 1 month, which was assessed in an intention-to-treat analysis. Randomisation was computer generated and only accessible to the osteopath practitioner. The parents, research assistants and paediatricians were masked to group assignment. Results One hundred twenty-eight mother–infant dyads were randomised, with 64 assigned to each group. In each group, five infants were lost to follow-up. In the intervention group, 31 of 59 (53%) of infants were still exclusively breast fed at 1 month vs 39 of 59 (66%) in the control group, (OR 0.55, 95% CI 0.26 to 1.17; p=0.12). After adjustment for suboptimal breastfeeding behaviour, caesarean section, use of supplements and breast shields, the adjusted OR was 0.44 (95% CI 0.17 to 1.11; p=0.08). No adverse effects were reported in either group. Conclusion OMT did not improve exclusive breast feeding at 1 month. Trial registration number NCT01890668 .