This study compared the incidence of acute respiratory infections (ARI) in exclusively breastfed infants versus not exclusively breastfed infants aged 61-180 days. A total of 200 infants were followed prospectively for 4 months each and divided into two groups: 100 exclusively breastfed infants and 100 not exclusively breastfed infants. A total of 232 ARI episodes were recorded, with 67 episodes in the exclusively breastfed group and 165 episodes in the not exclusively breastfed group. The incidence of ARI was higher in the not exclusively breastfed group compared to the exclusively breastfed group. Exclusive breastfeeding for the first 6 months was found to be effective in preventing ARI in infants aged 61-180 days.