: Breastfeeding is essential for infants providing them the much-needed nutrients for a health start. The World Health Organization recommends exclusive breastfeeding for the first six months of the infant’s life. The objective of this study was to assess the influence of nutritional education among fathers on exclusive breastfeeding practices for infants aged 0-6 months in Kisumu County, Kenya. An interventional study was conducted. The study setting was Kisumu East Sub County, Kenya. A total of 290 father-mother pairs were recruited into the study. Recruitment took place at Kisumu County hospital when the mothers were at 23-27 weeks gestational age. Pairs were randomized into either intervention or control group with 145 pairs per group. Pairs in the intervention group received nutrition education on breastfeeding (exclusive breastfeeding and male involvement), while those in the control group did not receive any intervention during the one-year research period. Quantitative data on exclusive breastfeeding practice, maternal and paternal knowledge and support towards breastfeeding were collected using an interviewer administered pretested questionnaire, while qualitative data were collected through 4 focus group discussions in both intervention and control groups. The proportion of infants fed only mother’s milk at 6 months was significantly higher (77.7 %) in the intervention group than in the control group (45.1%, p<0.001). Fathers in the intervention group who had been exposed to nutrition education on breastfeeding and were knowledgeable on exclusive breastfeeding were twice more likely to exclusively breastfeed. Nutrition education to fathers on breastfeeding impacts positively on breastfeeding rates.