To develop, implement, and examine the effect of a breastfeeding educational program on breastfeeding knowledge and practices of Egyptian mothers of preterm infants. An experimental design was used with a convenience sample of 60 mothers and their preterm infants who were born before 37 weeks of gestation. They were randomly assigned to intervention and control groups. Data collection instruments included breastfeeding knowledge questionnaire, observational checklist of mother's breastfeeding practices, breastfeeding diary, infant's and mother's profile form, and demographic information. A five-session breastfeeding educational program based on Bandura's Social Cognitive Theory was implemented with the intervention group during the infant's hospitalization and after discharge. Both groups were followed up to 3 months after discharge. Descriptive statistics, ANOVA, Chi-square, and regression were used to analyze the data. Mother's knowledge significantly increased for the intervention group but not the control group (p = 0.041). The intervention group showed gradual improvement in breastfeeding practices, i.e., started breast milk expression earlier and had more breast milk expression frequently than the control group. Of the intervention group, 80% were discharged on exclusive breastfeeding compared to 40% among the control group, and breastfeeding problems were less among the intervention group. The breastfeeding educational program was effective in improving breastfeeding knowledge and practices among mothers of preterm infants.