Background Hyperemesis gravidarum is severe forms of nausea & vomiting in pregnancy characterized by more than 5% weight loss and ketonuria. Although there is cases in Ethiopia, there are insufficient information regards determinant factors, mainly no research done in Amhara region. The finding helps to decrease hyperemesis gravidarum for those at high risk by early interventions like to take ginger tea, to eat small, dry, frequent & non-fatty foods and to visit health institution early which will decreases hospitalizations & maternal complications. Objective: To assess the determinants of Hyperemesis Gravidarum among pregnant women attending antenatal care at public & private hospitals, Bahir Dar city,North-West Ethiopia, 2022 Method: Facility based unmatched case control study were conducted on 444 (148 cases and 296 controls) from January 1-May 30. Women with diagnosis of hyperemesis gravidarum documented on the chart were considered as cases and women who attend antenatal care service without hyperemesis gravidarum were assigned as controls. Cases & controls were selected by a consecutive sampling technique. After the diagnosis of Hyperemesis gravidarum, the first two mothers come for antenatal care were taken as controls.Data were collected by interview using a structured questionnaire and check list also used that was adapted from reviewing different articles then coded and entered into EPI- Data version 3 and exported in to SPSS version 23 finally results were presented by using texts, tables and graphs. Multivariable logistic regression was performed to identify determinants of Hyperemesis Gravidarum at a p-value of less than 0.05.Adjusted odds ratio with 95% CI was used for direction of association. Result: From urban (AOR=2.717, 95% CI 1.693,4.502) ,primigravida (AOR=6.185, 95% CI 3.135, 12.202), first& second trimester of pregnancy (AOR=9.301, 95% CI 2.877,30.067) & (AOR=4.785, 95% CI 1.449,15.805) respectively, family history of hyperemesis gravidarum (AOR=2.929, 95% CI 1.268,6.765),helicobacter pylori (AOR=4.881 , 95% CI 2.053, 11.606) & Depression (AOR=2.195, 95% CI 1.004,4.797) were determinants of hyperemesis gravidarum. Conclusion: From urban, primigravida, being first and second trimester of pregnancy, family history of hyperemesis gravidarum, helicobacter pylori infection & depression were the determinants of hyperemesis gravidarum. Healthcare providers should decrease vomiting for mothers with primigravida & family history of hyperemesis gravidarum through psychological support & early treatment .Routing screening for helicobacter Pylori infection & mental health care for a mother with depression at the time of preconception care and counseling. Key words: Hyperemesis Gravidarum, Determinant factors