Background: The rising incidence of early-onset colorectal cancer (CRC) has prompted U.S. organizations to lower the recommended CRC screening age for average risk adults from 50 to 45 years old, while Canadian programs remain unchanged. Canadian guidelines also differ from the U.S. in preferentially screening with a fecal immunochemical test (FIT) and recommending against colonoscopies as a screening test. Differences in national healthcare administration warrants investigation into the resource impact of updating screening guidance in Canada. Methods: Microsimulation modeling was performed using OncoSim (version 3.6) to project health and economic outcomes of different CRC screening strategies based on Canadian population data. Four simulated birth cohorts of the Canadian population born between 1973–1992 were tracked for a 40-year span from the year the oldest in each cohort turned 40 until the youngest in the same cohort turned 75. Colorectal adenoma rates were adjusted according to cohort risk ratios estimated from historical incidence data to reflect real-world CRC rates. Outcomes were reported for the cumulative cohort. Results: Compared to FIT screening at age 50, FIT screening at 45 reduced deaths by 5,220, incidence by 11,980, and added 96,100 health-adjusted life years (HALY). Colonoscopy screening at age 45 led to 17,870 fewer deaths, 74,250 fewer cases and added 314,960 HALYs. FIT and colonoscopy screening at age 45 had incremental costs of CAD$3,259 and $7,881 per HALY gained vs. a FIT at age 50, respectively. Across screening strategies, the greatest benefits were observed in the youngest cohort. Colonoscopy screening at age 45 resulted in 10,679,540 more total colonoscopies than the current capacity of 8,966,979 with FIT screening at age 50. Lowering the screening age to 45 with a FIT increased colonoscopy demand by 329,555. The total cost of CRC care (screening, diagnosis and treatment) increased with lower screening ages and colonoscopy first modalities, while the cost of CRC management (diagnosis and treatment) decreased with lower screening ages and colonoscopy first approaches. Conclusions: Adjusting current CRC screening guidelines demonstrates significant resource implications with proportional health benefits. Lower screening ages and colonoscopy first approaches have the largest resource demand and greatest health outcomes, while the incremental cost per HALY gained for all screening strategies is modest compared to standard benchmarks.