Background COVID-19 pandemic is experienced intensely in our country like others. The presence of cancer in the patients is associated with morbidity and mortality in the course of COVID-19 disease. In this study, we aimed to evaluate the level of knowledge, attitude and behaivours regarding coronavirus disease in cancer patients. Methods This study is a single-center study which consists of 220 cancer patients who treated in our clinic. A questionnaire which consisted of three parts measuring the knowledge, attitudes and behaviours among cancer patients about COVID-19 was completed by each patient face-to-face during June, 2020. Results Most patients were familiar with the general information on COVID-19. Most cancer patients were aware of the symptoms of COVID-19 and that they were at greater risk. In 50% of the patients participating in the survey, it was observed that the covid-19 outbreak did not thought delaying cancer treatments. Half of the cancer patients who didn’t receive active cancer treatment preferred to have control tests performed at the time deemed appropriate by their doctors during the pandemic. 38.6% of them wanted to have control examinations done on the scheduled time. All of the patients wore masks when going out during the outbreak. Nearly all of the participants (99%) washed their hands to prevent contamination. 95% of the participants paid attention to social distance with other people. Contributors in the questionnaire with higher educational level had significantly higher knowledge mean scores compared to those with others. Conclusion In general, cancer patients are conscious about pandemic. They move with high compliance with their doctors in this period. Since COVID-19 infection is more severe in cancer patients, it is very important to evaluate these parameters to increase their knowledge and to correct their incomplete or incorrect information about this disease.