There is increasing evidence that improved agricultural technologies benefit smallholder farmers in sub-Saharan Africa. This evidence is however relatively clearer for innovations in smallholder crop production systems as compared to innovations in livestock production systems. Moreover, it is unclear whether the benefits of technology adoption in livestock systems are uniform across small and relatively large farmers. This study uses a national representative sample of 906 households to rigorously assess the impact of adoption of improved dairy cow breeds on enterprise-, household-, and individual child-level nutrition outcomes in Uganda. We find that adopting improved dairy cows significantly increases milk yield, household’s orientation to milk markets, and food expenditure. Consequently, adoption substantially reduces household poverty and stunting for children younger than age five. Considering heterogeneity, we find that adopting households with small farms increase milk yield, food expenditure and reduce poverty substantially while large farms increase not only ownmilk consumption and commercialization but also nutrition outcomes of children younger than age five.