BackgroundEmergency departments (ED) are an important site for screening patients with suicidal behaviors. However, there is insufficient data in low-and middle-income countries regarding the magnitude of suicidal attempts among patients attending EDs. Therefore, the present study aimed to screen suicidal behavior and factors associated with suicide in patients attending an ED of Addis Ababa Burn, Emergency and Trauma Hospital, Ethiopia.MethodA facility-based quantitative cross-sectional study was conducted between April and June 2018. A total of 398 participants were recruited using a consecutive sampling technique. The collected data collected includes structured questionnaires containing sociodemographic determinants, chronic medical illness conditions, substance use characteristics, social support level, common mental disorders (CMD) screening, suicidal behaviors assessment and suicidal attempts reason and method.ResultsThe prevalence of suicidal behavior and suicidal attempts were 8% and 6.3%, respectively. Suicide was attempted most frequently in the 18–24 age group. There was no overall difference in sex distribution for suicidal attempts. However, there were sex-based differences when the age group was taken into consideration. The commonest underlying reason for the attempt was social reasons (44%), while the most frequently reported attempt method was hanging (36%). No single factor was found to be significantly associated with the suicidal attempt.ConclusionAlthough suicidal behaviors are more common in patients attending the ED than in the general population, these facts have previously got little attention in patient attending EDs in low and middle income countries. The present findings support the need for a more detailed assessment of suicidal behaviours in patients attending ED and in patients with CMD.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12888-023-04949-9.