© 2020 Ceylan S et al. Licensee African Health Sciences.Background: Body mass index (BMI) of overweight and obese women is a risk factor for breast milk secretion. Aim: This study was conducted in a descriptive and comparative way in order to identify the relation between the breastfeed-ing success and self-efficacy of obese and non-obese mothers during postnatal period and to make a comparison between the obese and non-obese group. Methods: The study sample consisted of 113 obese and 111 non-obese mothers that met the study criteria who were hos-pitalized at the postnatal service of Health Education and Research Hospital in Ankara, September 2014-February 2015. Result: The mean BMI of obese women prior to the pregnancy was 31.41±2.4 while it was 22.25±2.8 for the non-obese women. As the BSS scores increase among both the obese and non-obese mothers, the LATCH breastfeeding success score averages increase as well (p<0.05, r:0.613). Conclusion: In the light of the data of, to increase the breastfeeding success among obese mothers, it is suggested that the perception of self-efficacy is enhanced, and additional consultation is provided on breastfeeding starting from the antenatal period. The trainings given to mothers by the midwife and nurse are supported with home visits especially in the obese women in the postnatal period in order for them to breastfeeding.