Abstract Objectives: to evaluate the effect of an intervention on the incidence of nipple trauma and the quality of breastfeeding technique in the first month of postpartum. Methods: this is a quasi-randomized intervention study with 180 puerperal women equally distributed between experimental and control groups. The intervention was performed at a maternity and consisted of an educational session on breastfeeding technique. A descrip-tive analysis of the groups’ characteristics was performed, comparing the frequencies of unfa-vorable parameters related to breastfeeding technique between groups. Pearson’s chi-square test and Fisher’s test were used, and p≤0.05 was adopted as the critical level of significance. Results: at 30 days, 64% and 15% of the mothers used the technique correctly, respec-tively, in the experimental and control groups with RR=4.87 (CI95%=2.93-8.34); NNT=1.96 (CI95% =1.61-2.72); p<0.001. In the experimental group, a decrease was observed in the unfavorable parameters of the breastfeeding technique (p≤0.05). The incidence of nipple trauma was 30% in the experimental group and 38.9% in the control group (p=0.21). Conclusions: the intervention was insufficient to prevent nipple trauma in the experi-mental group, but significantly improved the quality in the breastfeeding technique.