PURPOSE This study examined changes in patterns of cancer-related deaths during the first year of the coronavirus disease 2019 pandemic in the United States. METHODS We identified cancer-related deaths, defined as deaths attributable to cancer as the primary cause (underlying cause) or deaths with cancer documented as one of the multiple contributing factors (contributing cause) from the Multiple Cause of Death database (2015-2020). We compared age-standardized cancer-related annual and monthly mortality rates for January-December 2020 (first pandemic year) to January-December 2015-2019 (prepandemic) overall and stratified by sex, race/ethnicity, urban rural residence, and place of death. RESULTS We found that the death rate (per 100,000 person-years) with cancer as the underlying cause was lower in 2020 compared with 2019 (144.1 v 146.2), continuing the past trend observed in 2015-2019. By contrast, the death rate with cancer as a contributing cause was higher in 2020 than in 2019 (164.1 v 162.0), reversing the continuously decreasing trend from 2015 to 2019. We projected 19,703 more deaths with cancer as a contributing cause than expected on the basis of historical trends. Mirroring pandemic peaks, the monthly death rates with cancer as a contributing cause first increased in April 2020 (rate ratio [RR], 1.03; 95% CI, 1.02 to 1.04), subsequently declined in May and June 2020, and then increased again each month from July through December 2020 compared with 2019, with the highest RR in December (RR, 1.07; 95% CI, 1.06 to 1.08). CONCLUSION Death rates with cancer as the underlying cause continued to decrease in 2020 despite the increase in death rates with cancer as a contributing cause in 2020. Ongoing monitoring of long-term cancer-related mortality trends is warranted to assess effects of delays in cancer diagnosis and receipt of care during the pandemic.