Background:Underweight continues as a major public health problem in Ethiopia and it increase the risk of infections, morbidity, mortality and impairing mental and cognitive development.There is paucity of evidence on underweight in transformed and non-transformed woredas in Ethiopia. Objective:Compare child underweight and its associated factors among transformed and non-transformed woredas in East Gojjam zone, Northwest Ethiopia, 2022. Methods:A community based comparative cross-sectional study was conducted among 627 children aged between 6-59 months (314 from non-transformed and 313 from transformed woredas) in East Gojjam zone from May 18 to June 18, 2022. Stratified random sampling was used to reach study participants. Pretested and structured questionnaire was used to collect data. The WHO Anthro software was used to convert raw anthropometric data into Z-scores.Bivariable and multivariable logistic regression analysis were done. A p-value less than 0.05 were considered to declare as statistically significant. Results: - The prevalence of underweight among children innon-transformed and transformed woredas were 27.7% and 17.8 % respectively. Whereas, the overall prevalence of children underweight was 22.7 % (95% CI (19.0, 26.0 %).History ofdiarrhea in the past two weeks [AOR 2.49 (1.56, 3.98)], food insecurity [AOR 2.67 (1.60, 4.46)],household low monthly income [AOR 3.77(2.34, 6.08)], food distributed priority to other family members [AOR 1.64 (1.02, 2.65)] and unprotected drinking water source [AOR 1.82 (1.10, 2.99)] were thefactors significantly associated with underweight. Conclusion and Recommendation: -The overall prevalence of underweight among6-59 months of age children were22.7 %. Factors associated with underweight were unprotected drinking water source, food distributed priority to other family members, household low monthly income, food insecurity and history of diarrhea in the past two weeks prior to data collection. Therefore,improving safe water supply, hygiene and sanitation,knowledge of mothers on child feeding, and ensure food securityis recommended. Keywords:Underweight, Under-five children, Transformed woreda, Non-transformed woredas, Ethiopia