Background Of 133 million births globally, 3.7 million died in the neonatal period and 3 million are stillborn. The perinatal mortality rate in Ethiopia is 46 per 1000 pregnancies. However, area-specific information is limited in this regard. Therefore, this study aimed to determine the magnitude and determinants of adverse perinatal outcomes in Northern Ethiopia. Method An institution-based cross-sectional study was conducted by reviewing the medical records of mothers who gave birth between September 2015 and August 2016. The completeness and consistency of data were checked. Descriptive statistics were computed. A multinomial logistic regression model was fitted to identify determinants of adverse perinatal outcomes. Odds ratio with 95%CI was used and variables that had a P -value of < 0.05 in the final model were considered statistically significant. Result The magnitude of adverse perinatal outcomes was 214/799(27.47 %). Out of that, 10.8% had a perinatal mortality outcome, and 16.7% had a perinatal morbidity. Not using modern contraceptives(AOR = 1.7, 95% CI: 1.1-2.7), labor induction or augmentation(AOR = 3.0, 95% CI: 1.2-7.8), obstetric complications(AOR = 2.2, 95% CI: 1.1-4.5), attending antenatal care(AOR = 0.4, 95% CI: 0.2-0.8), primigravida (AOR = 0.5, 95% CI: 0.3-0.9), had no history of medical illness(AOR = 0.5, 95% CI: 0.3-0.8), and urban residency(AOR = 1.9, 95% CI, 1.1-2.9) were the significant determinants of perinatal outcome. Conclusion The magnitude of adverse perinatal outcomes was considerable and 1 in 5 neonates either had morbidity conditions or died. Improving family planning utilization, ANC, referral linkage, and management of obstetric complications could help to reduce the undesirable consequences of perinatal outcomes.