Background: Developing effective cancer control programmes requires information on the future cancer burden in an ageing population. In our study we predicted the burden of cancer in Catalonia from 2015 to 2025. Methods: Bayesian age-period-cohort models were used to predict the burden of cancer from 2015 to 2025 using incidence data from the Girona and Tarragona cancer registries and cancer mortality data from the Catalan mortality registry. Using the Bashir-Estève method, we divided the net change in the number of cases between 2015 and 2025 into changes due to population size (S), cancer risk (R) and age (A) distribution. Results: By 2025, there will be 21,743 new cancer cases in men (40% aged > 74 years) and 17,268 in women (37% aged > 74 years). More than 40% of the new cases will be diagnosed among population aged 74 and older in prostate, colorectal, lung, bladder, pancreatic and stomach cancers in men, and in colorectal, pancreatic and bladder cancers and leukaemia in women. During 2015-2025, the number of new diagnoses will increase by 5.5% in men (A + R + S = 18.1% − 13.3% + 0.7% = 5.5%) and 11.9% in women (A + R + S = 12.4% − 1.1% + 0.6% = 11.9%). Overall cancer mortality rates will continue to decrease during 2015-2025. Lung cancer will be the most lethal cancer among men (N = 2705) and women (N = 1174). Conclusions: The increase in the number of cancer cases in Catalonia from 2015 to 2025 will mostly affect the elderly, prompting the need for increased collaboration between geriatricians and oncologists.