Aims: In the present study, it was aimed to determine the death anxiety and diabetes self-management perceptions of diabetes mellitus (DM) patients. Methods: The descriptive and correlational study was conducted on 351 DM patients who visited the internal medicine outpatient clinic of a government hospital between 20.02.2022 and 20.05.2022. The Patient Identification Form (PIF), Death Anxiety Scale (DAS), and Diabetes Self-Management Perception Scale (DSMS) were used as data collection tools. The descriptive statistics, Mann-Witney U, Kruskall-Wallis, and Spearman correlation tests were used to evaluate the data. In the study, p<0.05 was considered significant. Results: It was determined that 39.3% of DM patients participating in the study experienced fear of death. It was determined that the average score of the patients on the death anxiety scale was 9.24±3.70, and the average score on the diabetes self-management perception scale was 24.84±3.28. It has been determined that the self-management skills of patients who are primary school graduates and patients who develop acute complications due to DM are higher. In terms of death anxiety scale scores, it was determined that women had higher death anxiety levels than men and patients with DM-related fear of death compared to others. There was no significant relationship between the Death Anxiety Scale Total Score and the Diabetes Self-Management Scale Total Score (p>0.05). Conclusion: In the study, it was determined that patients experienced more severe death anxiety and moderate death anxiety. Additionally, the self-management of DM patients was found to be above average. No relationship was found between the patients’ Death Anxiety Scale and Diabetes Self-Management Perception Scale score averages. The mean Diabetes Self-Management Perception Scale scores of primary school graduates and patients with DM-related complications are significantly higher than others.