Objective: Patients with cancer have an increased risk of severe coronavirus disease-2019 (COVID-19) because their immune systems are suppressed due to cancer treatments or cancer itself. Therefore, patients with cancer are prone to COVID-19 infection. In this study, we evaluated the anxiety of patients receiving cancer treatment in our oncology department during the COVID-19 pandemic. Material and Methods: This descriptive cross-sectional study consisted of 220 patients receiving cancer treatment in the medical oncology clinic of our hospital between 01 and 30 April 2020. Study data were obtained using a questionnaire consisting of 26 questions. The Hospital Anxiety and Depression Scale was used to determine the patients’ psychological distress. The scale results were compared with the results of Kruskal-Wallis, Mann-Whitney U, and chi-square tests. Results: We observed that 80 (36.4%) and 40 (18.2%) of the 220 patients studied had risks of depression and anxiety, respectively. In this study, 46.4% of the patients believed that their illness was being negatively affected by the COVID-19 pandemic, and 45.5% of the patients worried that their treatment would be interrupted during this period. Conclusion: Our results suggest that patients with cancer need more psychosocial support than do the general population during this pandemic period. These needs should be considered while planning oncological health services, and appropriate arrangements should be made.