Background:Teenage pregnancy isa pregnancy occurs within the maternal age of 10-19 year.Adverse maternal outcome caused by teenage pregnancy are major public health problemsin developing country.Teenage pregnancy increases the risk of adverse maternal outcome compare to adult mothers.Ethiopian Federal Ministry of Health developed new national adolescent and youth health strategy to reduce teenage pregnancy by halve.Some of the efforts done, teenage pregnancy remains high in Ethiopia. Most studies conducted in Ethiopia only assessing magnitude of teenage pregnancy rather than address adverse maternal outcome. Objective:To assess adverse maternal outcome and associated factors among teenage and adult mothers who gave birth in West Gojjam public hospitals,North West Ethiopia, 2022. Methods:Facility based comparative cross-sectional study was conducted in West Gojjamzone public hospitals from April 30 –June 30, 2022 among 785 mothers (386 teenage and 399 adult).A systematic random sampling was used to select study participants. Data were collected using interview administered questionnaire.Both data entry and analysis was made using Epi-data version 3.1 and statistical product and service solution.Bivariate and multivariate logistic regression was used. Adjusted odds ratio with 95% CI used to measure the strength of association between explanatory variables and outcome variable.P- value<0.05 at multivariate logistic regression considered as statistically significant with adverse maternal outcome. Results:The proportion of adverse maternal outcome among teenage and adult mothers was 33 %( 95% CI, 28.2 - 37.4) and 22.1 %( 95% CI, 18-26.2) respectively. Similarly, proportion of preeclampsiaperineal tear and anemia were significantly higher in teenage mothers.Rural residence [AOR: 1.761 (95% CI, 1.189, 2.609)], late initiation of antenatal follow up [AOR: 1.749(95% CI, 1.226, 2.495)] and no attend complete antenatal visit [AOR: 1.671(95% CI, 1.040, 2.685) were also factors significantly associated with adverse maternal outcome. Conclusion:Adverse maternal outcome among teenage mothers were significantly higher when compared to adult mothers.Increaseaccesses to skilled care for populations living in remote areas and also promoted community-organized transport scheme and provided community mobilization activities to increase awareness on ANC follow up were recommended. Key word: Teenage pregnancy, adult pregnancy, adverse outcome, Ethiopia