Abstract: Background: Undernutrition was casing more than half of under-five mortality where it is still preventable problem. There is no study that shows the association of maternal age with child undernutrition. Objective: To compare the magnitude of wasting and associated factors among children born to women aged 15-19 years and those aged 20-49 years in Damot Gale woreda, southern Ethiopia, 2023. Methods: comparative cross-sectional study was conducted from January 2021 to August 2023 Stratified random sampling technique was used to select 2121 mother-child pair of study participants. Data were entered into Epi Data V4.6 and the Z-scores of indices, WHZ, HAZ, WAZ were calculated using WHO Anthro. Then, data were exported to SPSS V23 for further analysis. Multivariable logistic regression analysis was done to identify the independent determinants of stunting, wasting and underweight separately and variables with a p-value of <0.05 and 95%CI of AOR was used to declare statistically significance. Result: the overall prevalence of wasting among the study population was 12.7%. However, when we come to maternal age category, there was significant difference between mothers of age group 15- 19 years and 20-49 years old. The prevalence of wasting was 16.5% (95%CI: 14.6%, 18.0%) found to be high among the children 6-59 months born to mothers of age group 15-19 years than children born to mothers of age group 20-49 years old, (16.5%, 95%CI: 14.8%, 18.0%). Conclusion: this study showed that the prevalence of wasting found moderate and there was significant difference between children born to mother’s age category. Maternal education, history of illness in the last 14 days, child sex, BMI, ANC, dietary diversity score, monthly income, birth order, health facility distance in minutes were factors associated with undernutrition. Zonal, district as well as health facilities should intervene on nutrition related services.

Under nutrition, early marriage, Damot Gale Woreda