Acute Respiratory Infection (ARI) is one of the main causes of death of infants and children under five years old in the developing countries. The knowledge of mothers of severe ARI symptoms and immediately seeking modern treatment in severe ARI cases will decrease the mortality rate in infant and children under five. The National Socio-Economic Survey (SUSENAS) I998 has ident$ed mothers who had infants and children under five years old who suffered cough, colds, fever as well as the treatment choices in one month before the survey. This paper analyzed the pattern and the determinants of health seeking behavior of ARI. The analysis method was descriptive and analytical with simple logistic regression (PcO.25 for candidate covariate) and multiple logistic regression (P