© 2022 John Wiley & Sons Ltd.Introduction: Increased stress levels caused by the pandemic might cause delays in cancer treatment. We conducted a survey among cancer patients undergoing treatment to evaluate their psychological wellbeing and treatment adherence during Coronavirus disease 19 (COVID-19) pandemic. Material and Methods: Patients receiving active chemotherapy at a private oncology center between January and May 2021 were included. Healthy volunteers were employees of a district health directorate with no history of cancer or chronic disease. Treatment adherence was described as compliant if the prescribed treatment was received within a week and the information was gained from patient charts. Hospital anxiety and depression scale (HADS) and COVID-19 phobia scale (CP19-S) were administered to participants. Results: 402 participants were included; 193 (48%) were cancer patients. The mean age of the participants was 44 years old and 68% of the participants were female. All participants' CP19-S mean score was 47.9. Patient group had significantly lower CP19-S (p = 0.006). Chronic disease and history of a shocking event were the factors associated with CP19-S. All participants reporting hospital anxiety were found to have significantly higher COVID-19 phobia levels (p < 0.05). Patients' mean HADS-anxiety score was significantly higher (7.3 vs. 6.5, p = 0.027). COVID-19 phobia was an independent factor increasing the level of anxiety and depression in both groups. Adherence to treatment was 100%. Conclusion: The pandemic increased levels of anxiety, however, cancer treatment continued to be a priority in patients' lives. Strategies should be developed to support oncology patients cope with the pandemic and increase their courage to avoid treatment delays.