Fathers' support is an essential component in ensuring success in improving infant feeding practices which have the overall impact of reducing infant mortality rates by 19%. Fathers are usually not targeted with information on infant feeding at the health facility or community level. Fathers have been identified as lacking knowledge, hence, not able to support the recommended infant feeding practices. The study was conducted in Kisumu East Sub County, Kisumu County, which was selected because of the high infant mortality rate in the region. A nutrition education intervention strategy was employed targeting the fathers with information on breastfeeding and complementary feeding through an experimental study in which 290 father-and-mother to be paired were recruited. There was randomization of study participants into either intervention group (145 pairs) where nutrition education was given, or control group (145 pairs) where nutrition education was not given. Recruitment was of all the women who were 6 months pregnant and attending antenatal clinic at Kisumu County Hospital between January-April 2016. The women gave the contacts of the father-to-be, which enabled follow-up to reach the fathers. Quantitative data were collected from the fathers through a pre-tested structured questionnaire that explored their knowledge of breastfeeding pre-intervention. Qualitative data were collected through focus group discussions to assess knowledge, beliefs, and practices on breastfeeding pre-intervention and post-intervention (9 months later).Results did not show any significant differences in the knowledge level on breastfeeding of fathers in the intervention and control group pre-intervention (p>0.05).Significant differences were observed post-intervention on knowledge levels on initiation of breastfeeding within an hour of birth (p =.01), continuation of breastfeeding for 2 years and beyond (p =.02) and exclusive breastfeeding (p =.02)and group affiliation. A Wilcoxon signed-rank test showed a statistically significant change in knowledge of the fathers in the intervention after receiving the nutrition education sessions (Z = -10.181, p = 0.000). The group discussions showed that fathers largely saw their role as the provision of food for maternal and infant feeding pre-intervention in both groups, while fathers reported additional roles postintervention in the intervention group including being a source of motivation and information to the mother. In conclusion, fathers have low knowledge levels on breastfeeding process which in turn affects their influence on breastfeeding practice. Nutrition education involving the fathers increases their knowledge on breastfeeding and influence to breastfeeding practice ultimately contributing to improved breastfeeding practices.