The primary aim of this study is to examine the relationship between COVID-19 anxiety and death anxiety among adults in the post-pandemic period. Additionally, the study aims to adapt the COVID-19 Anxiety Scale into Turkish and evaluate its psychometric properties. This research was conducted within the framework of the relational screening model. The COVID-19 Anxiety Scale was adapted into Turkish, and validity and reliability analyses were performed. Data were collected using the COVID-19 Anxiety Scale and the Death Anxiety Scale. The participants consisted of 307 adults from Turkey. The relationship between COVID-19 anxiety and death anxiety was examined using correlation and stepwise regression analyses. Factor analyses were conducted for the scale adaptation process. According to the findings, there were positive relationships between the subdimensions of death anxiety—namely Fear of the Unknown About Death, Thought and Witnessing of Death, and Fear of Pain—and COVID-19 anxiety. Furthermore, the results indicated that the COVID-19 Anxiety Scale is a valid and reliable instrument for use in the Turkish cultural context. In this regard, it can be concluded that death anxiety plays a significant role in understanding anxiety levels among adults during and after pandemic periods. This study strengthens the theoretical understanding of the relationship between death anxiety and pandemic-related anxiety and demonstrates that the subdimensions fear of the unknown, thought and witnessing of death, and fear of pain significantly predict COVID-19 anxiety in adults. The findings show the psychological effects of death-related fears during the pandemic and their potential long-term impacts on mental health. In addition, the results emphasize that managing death anxiety is important for mental health professionals and policymakers in reducing COVID-19-related psychological distress.