Aims: In this study, it was purposed to evaluate demographic, clinical, laboratory characteristics, bleeding etiologies, risk factors, comorbidity and mortality of the patients who were interned with the diagnosis of upper gastrointestinal system bleeding. Methods: In this study, 157 patients those hospitalized to Ministry of Health Beyoğlu Public Hospitals Association Gaziosmanpaşa Taksim Training and Research Hospital Internal Medicine Clinic with the diagnosis of upper gastrointestinal bleeding between 1 April 2014 and 1 April 2015 were evaluated retrospectively. Age, gender, duration of hospitalization, comorbidity, prescription story, need and amount of transfusion, endoscopic findings, hemoglobin (Hgb), blood urea nitrogen (BUN), urea, creatinine (Cr) values on admission, complication and mortality data were recorded. IBM SPSS (Statistical Package for Social Sciences) for MAC 21.0 program was used for statistical analysis in order to evaluate the data. Results: Patient were aged between 17 and 94 .The mean age was 59.04±20.55. 95 (68.35%) of patients were male and 44 (31.65%) were female with the male/female ratio of 2.15/1. While 64.75% of the patients in our study had at least one additional disease, no additional disease was detected in 35.25%. Endoscopic procedure was peformed 89.93% of patients for both diagnosis and treatment. Exitus was seen in 7 patients and mortality was detected as 5.04%. Median age of deceased patients was 75.28±15.39. Median age of surviving patients was 58.18±20.47. Conclusion: Our study revealed that upper GI bleeding is an important cause of mortality and morbidity despite advanced treatment options and intensive care conditions. The most important risk factors responsible for mortality are advanced age and the presence of comorbidities, as seen in our study.