Whole grain consumption has been associated with the reduced risk of several chronic diseases with significant healthcare monetary burden, including cancer. Colorectal cancer (CRC) is one of the most common cancers globally, with the highest rates reported in Australia. Three servings of whole grains provide a 15% reduction in total cancer and 17% reduction in CRC risk; however, 70% of Australians fall short of this level of intake. The aim of this study was to assess the potential savings in healthcare costs associated with reductions in the relative risk of CRC and total cancer mortality following the whole grain Daily Target Intake (DTI) of 48 g in Australia. A three-step cost-of-illness analysis was conducted using input parameters from: (1) estimates of current and targeted whole grain intakes among proportions (5%, 15%, 50%, and 100%) of the Australian adult (≥20 years) population; (2) estimates of reductions in relative risk (with 95% confidence intervals) of CRC and total cancer mortality associated with specific whole grain intake from meta-analysis studies; and (3) estimates of annual healthcare costs of CRC and all cancers from disease expenditure national databases. A very pessimistic (5% of population) through to universal (100% of population) adoption of the recommended DTI in Australia were shown to potentially yield savings in annual healthcare costs equal to AUD 1.9 (95% CI 1.2–2.4) to AUD 37.2 (95% CI 24.1–48.1) million for CRC and AUD 20.3 (95% CI 12.2–27.0) to AUD 405.1 (95% CI 243.1–540.1) million for total cancers. As treatment costs for CRC and other cancers are increasing, and dietary measures exchanging whole grains for refined grains are not cost preclusive nor does the approach increase energy intake, there is an opportunity to facilitate cost-savings along with reductions in disease for Australia. These results suggest specific benefits of encouraging Australians to swap refined grains for whole grains, with greater overall adherence to suggestions in dietary guidelines.