Background: Breastfeeding is the most cost-effective intervention for reducing infant morbidity and mortality worldwide. Having flat or inverted nipples is among the reasons that prevent exclusive breastfeeding. Hoffman's exercise is a manual exercise that may help break adhesions at the base of the nipple that keep it inverted. Aim: To determine the effect of Hoffman's exercise on successful breastfeeding and satisfaction among postnatal women with flat and inverted nipples. Design: a quasi-experimental research design. Setting: The study was conducted at the postnatal unit of Damanhour Medical National Institute. Subjects: A convenience sample of 80 postpartum women Tools: three tools were used for data collection. Tool I: Socio-demographic and reproductive history structured interview schedule. Tool II: LATCH scale for the assessment of the level of breastfeeding. Tool III Maternal Breastfeeding Evaluation Scale (MBFES) is the Likert scale to assess maternal satisfaction with breastfeeding response. Results: Findings of the present study revealed that the total score of the LATCH scale was statistically significantly increased among the study group after intervention (p=<0.001). Regarding the degree of satisfaction with breastfeeding following the intervention, there were highly statistically significant differences between the analyzed groups (p<0.001), favoring the study group. In addition, the study findings showed that 42.5% and 27.5% of the subjects in the study group were either very satisfied or satisfied respectively, compared to only 5% and 7.5% of the subjects in the control group after intervention. Conclusion: The study concluded that postnatal women who practice Hoffman's exercise exhibit higher scores on the LATCH scale which means that Hoffman's exercise had a positive effect on the level of breastfeeding and women's satisfaction. Recommendations: Hoffman's exercise should be recommended as a safe, simple, painless, and effective, non-pharmacological method for treating flat and inverted nipples.