With the costs of cancer care rising, understanding the cost patterns across health services and over the course of disease is a crucial first step to allow us to better manage care for cancer patients. Our objective was to estimate the long-term costs of cancer care, across the continuum of health services and the trajectory of disease, in British Columbia (BC) and Ontario. We used administrative health data, including physician claims, prescription drug claims, hospital records and community care records, to measure health services used by patients diagnosed with one of 21 different cancers in both provinces. Costs were allocated to phases of care: 3 months before diagnosis, 6 months of initial treatment, the last year of life (for patients who died), and the intervening continuing care period. These costs were applied to 25-year survival estimates to calculate costs over the long term. We found some differences between provinces, although the patterns were consistent across phases of care, and across cancer types. With this study we are advancing the understanding of cancer costs by using population-based data and robust costing methods to evaluate costs across different health services and between provinces. These long-term cost estimates, and the observed patterns, will be valuable inputs for evaluation of future policy decisions in Canada and elsewhere.