Introduction: Severe acute malnutrition is a major problem among developing countries and it is one of the major causes of mortality and morbidity in Ethiopia. The impact is more severe among children age 6–23 month’s children. Severely malnourished children are nine times more likely to die than healthy children. Identification of the determinants of severe malnutrition under the age of two years can significantly reduce the burden of child morbidity and mortality. Objective- This study was aimed to assess predictors of severe acute malnutrition among 6-23 months children in Bahir Dar city public hospitals, Northwest Ethiopia, 2020. Methods- Institutional based unmatched case-control study was conducted among a total sample size of 201 children (67 cases and 134 controls) in Felege Hiwot Comprehensive Specialized Hospital and Tibebe Ghion Specialized teaching hospital, from February15–March 30, 2020. Children diagnosed as severe acute malnutrition were considered as cases and with other problems were control groups. The study participants were selected from pediatrics units in the two specialized hospitals. Data were collected using structured pretested questionnaire through interview. The data were entered into Epi data version 3.1 and exported to SPSS software version 23 for analysis. Variables with (p≤ 0.25) in bivariable analysis were entered to multivariable logistic regression. For multivariable analysis, a backward model was selected with 95% confidence interval. Statistical significance was declared at P< 0.05. Results: In this study, 67 cases and 134 controls of children with their mothers were included with the overall response rate of 100%. After multivariable logistic regression analysis, significantly associated variables with severe acute malnutrition were; family size >5 (AOR=3.89, 95%CI=1.19-12.70), average perceived birth weight (AOR= 0.048, 95%CI=0.015-0.148) and large perceived birth weight (AOR=0.023, 95%CI= 0.002-0.271), introduction of complementary feeding before six months (AOR= 6.21, 95%CI= 1.44-26.76) and dietary diversity score <4 groups (AOR= 11.41, 95%CI= 4.10-31.73). Conclusion and recommendation: In this study, dietary diversity, family size, perceived birth weight and initiation of complementary feeding were significantly associated with malnutrition. Therefore, emphasis should be given to improve infant and young child feeding practices especially timely initiation of complementary feeding and dietary diversity. Keywords: Bahir Dar, predictors, under two year children, severe acute malnutrition, Ethiopia