Background: Cancer is the second leading killer in the United States, but there is no comprehensive analysis evaluating total cancer costs by cancer and treatment modality. Methods: Data from the 2013 inpatient (100%), outpatient (100%), and carrier (5%) Medicare Limited Data Set Standard Analytic Files were queried for claims filed for International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes for all cancer diagnoses. Claims associated with the ICD-9 codes for professional fees were analyzed by Current Procedure Terminology (CPT) code to determine resource allocation by disease. Outpatient oral chemotherapy costs were obtained from the National Average Drug Acquisition Cost database for 50 drugs used for cancer treatment in 2013. Results: $27.9 billion was spent on cancer treatment of which $12 billion (43%), $6.5 billion (23%), and $1.1 billion (4%) was allocated to professional, inpatient facility, and outpatient facility fees, respectively. Oral and hospital-based chemotherapy accounted for 17% ($4.7 billion) and 15% ($4.3 billion) of all cancer costs, respectively. Lung/thoracic cancer ($2.9 billion) had the highest total annual cost and multiple myeloma ($9,019, SD $19,962) is the most expensive cancers to treat annually per patient. Average out-of-pocket expenses are $470 (SD 287), which is 12% of the annualized per patient costs. Conclusions: In 2013, cancer accounted for only 5% of Medicare spending. Chemotherapy costs accounted for approximately a third of total spending and are likely to rise as innovation continues. Out-of-pocket spending can place a financial burden on cancer patients requiring more expensive treatments.