The most common reasons cited by women for giving up breastfeeding early can be attributed to ineffective positioning and attachment and are therefore preventable. This study aimed to determine whether a 4-h training programme in 'hands off' positioning and attachment support increases midwives' knowledge and problem-solving skills. Using an unrelated comparison group and a pre- and post-intervention design, 108 midwives (experimental group) completed a 4-h standard breastfeeding training workshop focusing on effective positioning and attachment and the use of hands-off teaching methods. Knowledge and problem-solving skills were assessed using a modified form of the previously validated Breastfeeding Support Skills Tool. Pre- and post-training scores were compared with those of 27 student midwives (control group) who undertook the same assessments but without the breastfeeding training. Baseline knowledge scores of the midwives and the student midwives did not differ significantly (average difference 0.7 points to qualified midwives' advantage, 95% CI = -3.4 to 1.9). Following training, the qualified midwives' total scores increased significantly (7.2 points, 95% CI = 6.2-8.2). Minimal changes (1.4 points, 95% CI = -0.15 to 2.9) in students' scores were found. The additional increase owing to training above that which might be expected due to practice (i.e. the average difference in change scores between the two groups) was 5.8 points (95% CI = 3.75-7.96), representing a large effect size for the training (d = 0.95). There is a large variation in the breastfeeding knowledge of midwives working in post-natal care and, on average, they are no more skilled than senior student midwives. The study has shown that a 4-h workshop in a positioning and attachment intervention, using a 'hands-off' approach, can increase midwives' knowledge of breastfeeding support relevant to the immediate post-natal period. It is applicable to all midwives, and could be a cost-effective way of improving the ability of mothers to begin and continue to breastfeed successfully.