Background: In Indonesia, Acute respiratory infection (ARI) and diarrhea-related morbidity and mortality in children less than five years old still remain a significant public health concern. In this relation, energy, protein, zinc, and vitamins C, B, D, E, and A are essential nutrients to mitigate morbidity and mortality. Vitamin A was shown to play a crucial role in human development, growth, and immune function that can protect infants against infectious diseases such as  ARI and diarrhea. So this study aimed to compare the effect of beef
liver and vitamin A supplementation for breastfeeding mothers on the incidence of ARI and diarrhea in infants.
Methods: In a randomized control trial design, 40 participants aged 20-35 years were allocated into two groups of beef liver and vitamin A supplementations. The beef liver supplementation group received eight servings during two months postpartum, or no later than the 7^th day after giving birth; while the vitamin A supplementation group received two vitamin A capsules no later than the 7^th day postpartum.
Results: The incidence of ARI significantly differed, while there was no significant difference in incidence of infant diarrhea between the two groups.
Conclusion: In breastfeeding mothers, administering beef liver (75 grams/ day equivalent to 402,000 IU) could reduce the frequency of ARI and infant diarrhea more effectively than supplementation with two vitamin A capsules (equivalent to 400,000 IU). There was no difference in morbidity of infant diarrhea for mothers who received two vitamin A capsules.