Background: Hypertension is one of the major health problems that can cause significant rnmorbidity and mortality in the world. It affects about 1.13 billion world population. 1-2% ofrnthis population have hypertensive crisis. Hypertensive crisis is becoming the main health issuernin countries with low-income level. However, limited studies have been conducted in Ethiopia.rnThe aim of this study is to assess determinants of hypertensive crisis among patients visitedrnadult emergency department of selected public hospitals in Addis Ababa, 2021 rnMethod: Hospital based unmatched case-control study was conducted among 85 cases andrn170 controls at adult emergency department of selected public hospitals in Addis Ababa from rnMarch 15 to May 15 2021. Patients presented with hypertensive crisis were considered asrncases and hypertensives but without hypertensive crisis were considered as controls. Data wererncollected by trained nurses using structured questionnaire and entered to Epi Data version 4.6rnand exported into SPSS version 26 for analysis. Descriptive statistics was done and presentedrnusing text, frequency tables, charts and graphs. Binary logistic regression was done andrnvariables with p-value less than 0.25 were eligible for the final model. A multivariable logisticrnregression was also performed. Finally, statistical significant level was declared at a p-value ofrnless than 0.05. rnResult: The proportion of participants presented with history of previous HTN was higherrnamong cases than controls (82.4% and 64.1%) respectively and the likelihood ratio of rnhypertensive crisis was 3.6 times (AOR= 3.621: 95% CI 1.634,8.024,P=0.002) higher amongrnparticipants with history of previous HTN compared to without history of previous HTN.rnThere was also 4 times increased risk of hypertensive crisis among participants presented withrndiabetes mellitus than participants presented without it (AOR=4.179: 95% CI 2.064, 8.643,rnP=0.000). Similarly, participants presented with heart failure had 3 times higher odds (AOR=rn3.056: 95% CI 1.516, 6.162, P=0.002) compared to participants without heart failure.rnConclusion: This study demonstrated statistically significant association of unemployment,rndiabetes mellitus, stroke, heart failure, history of previous hypertension, family history ofrnhypertension and regular follow up with hypertensive crisis. The government, health facilitiesrnand health care workers should give attention for hypertensive crisis and the associatedrndeterminants.