Acute Respiratory Infection (ARI) is the most one of the children death cause in developing country. The giving of exclusive breast feeding and the environment become the factors that influence of Acute Respiratory Infections. This research is purposed to know the relation between exclusive breast feeding with the number of ARI cases in flat unit of Bandung Bondowoso Puncak Gading, Kaligawe Sawah Besar and Bedagan Semarang. The research is using analitic observational method with Cross-Sectional design. The research was done for twelve month baby in flat unit of Bandung Bondowoso Puncak Gading, Kaligawe Sawah Besar and Bedagan Semarang with 120 babies for samples, that have fulfilled the inclusive criteria and exclusive criteria. The data that was used are primer data from the quetioners, that was filled by the researcher when dong the observation in flat unit of Bandung Bondowoso Puncak Gading, Kaligawe Sawah Besar and Bedagan Semarang. Then the data was analyzed by chi square to know the relation betweeb exclusive breast feeding with ARI cases. Furthermore, it was tested with coefisien to know the closeness relation between exclusive breast feeding with ARI cases. The result of research with chi square test was got p = 0,000 and the result of coefisien contingensi test was 0,663. The conclusion of the research is, there are relation between exclusive breast feeding with ARI cases in flat unit of Bandung Bondowoso Puncak Gading, Kaligawe Sawah Besar and Bedagan Semarang with the closeness level is strong.