Background: Knowing the risk factors for patients in intensive care units (ICUs) facilitates patient's management. The goal of this study was to determine the risk agents that influence our medical ICU mortality. Patients and methods: This 11-month retrospective trial was managed in the medical ICU. In this study, 340 patients who were followed up for at least 24 hours in ICUs were accepted. The clinical data on patients were recorded retrospectively, and the mortality-related factors were analyzed. A regression analysis was also performed to determine the independent risk factors for ICU mortality. Results: The median age was 73 (53–82) years. The death rate was 23.8%. Length of stay (LOS) in ICU was 3 (2–5) days, and APACHE-II (acute physiologic and chronic health evaluation) score was 19 (13–25). The prevalence of chronic diseases was not dissimilar except acute and chronic renal failures among survivors and deceased patients (p >0.05). Acute and chronic renal failures were higher in deceased patients than in survivors and were statistically important [107 (41.3%) vs 47 (58%), p = 0.008] and 38 (14.7%) vs 22 (27.2%), p = 0.01], respectively. In the binary logistic regression analysis, age, APACHE II score, need for invasive mechanical ventilation (IMV), decreased serum albumin levels, and increased creatinine levels were established to be independent risk factors for death [(OR (odds ratio): 1.045 (1.009–1.081), p = 0.013, OR: 1.076 (21.008–1.150), p = 0.029, OR: 19.655 (6.337–60.963), p = 0.001), OR: 2.673 (1.191–6.024), p = 0.017, OR: 1.422 (1.106–1.831), p = 0.006)], respectively. Conclusion: The most significant risk agents of death were determined through high APACHE II score, decreased serum albumin levels, and increased creatinine levels.