1559 Background: Cancer remains a substantial and unique burden on society. While the impact of changing demographics on cancer incidence has previously been characterized (Smith et al, JCO, 2009), this has not been done with updated population data. Our objective was to update projections on the number of new cancer diagnoses in the United States by age and gender through 2040. Methods: Population-based cancer incidence data were obtained using SEER 18 delay-adjusted data. Population estimates were made by age, race, and gender using the 2010 US Census data population projections to calculate future cancer incidence rates. Trends in age- adjusted incidence rates for 23 cancer types were calculated as previously described (Edwards et al, Cancer, 2014). Results: From 2020 to 2040 the projected total cancer incidence will increase by almost 30% from 1.86 million to 2.4 million. This increase is due to the projected increase in population growth, particularly in older individuals. The population of older adults will represent a growing proportion of total cancer diagnoses. Specifically, patients ≥65 years old will make up 69% of all new cancer diagnoses, while 13% of new diagnoses will be in patients ≥85 years old by 2040 (see Table). Cancer diagnoses in females are projected to rise 27%, while male cancer diagnoses are projected to increase by 32% from 2020 to 2040. The incidence rates for lung, colorectal, and prostate cancer are expected to decline, while those for thyroid, liver, melanoma and myeloma are expected to increase. Conclusions: The landscape of cancer care will continue to change over the next several decades. The burden of disease will remain substantial and will continue to disproportionately affect older adults. The growing proportion of older cancer patients and changes in site-specific cancer incidence rates remain of particular interest. These projections should help guide future health policy and research priorities. [Table: see text]