INTRODUCTION: Medical and other cannabis use by cancer patients continues to increase. Reasons for use include management of psychosocial stressors, physical and psychological symptoms. We explored the effect of the coronavirus disease 2019 (COVID-19) pandemic on on patients' cannabis use, hypothesizing that users would be increasing their use due to heightened stress and increased uncertainty. METHODS: Participants were part of an anonymous online survey of cannabis use in cancer. Items specific to COVID-19 were administered between April and June 2020. RESULTS: Thirty-one percent of respondents (n = 26) confirmed they used cannabis during COVID-19. The top 5 reasons for use were sleep, anxiety, nausea, pain, and appetite. Ninety-two percent denied they were using cannabis for new or different symptoms. Eighty-one percent were using about the same amount as before, 11.5% were using less, and 8% more. Only 12% reported that product cost affected their use and that they had changed the way in which they used cannabis. Eight percent were stockpiling product so that they did not run out during the pandemic. CONCLUSIONS: The percentages of those reporting a change in cannabis use were modest. Increased use may reflect efforts to relieve stress. Decreased use may reflect barriers to securing unregulated products and perceived vulnerability to the effects of infection on the respiratory system. As the pandemic continues to evolve, it will be important to monitor its effects on cancer patients as it relates to psychosocial stressors, psychological symptoms, and cannabis use.