BACKGROUND:Health insurance plans are increasingly offering mailed fecal immunochemical test (FIT) programs for colorectal cancer (CRC) screening, but few studies have compared the outcomes of different program models (eg, invitation strategies). METHODS: This study compares the outcomes of 2 health plan-based mailed FIT program models. In the first program (2016), FIT kits were mailed to all eligible enrollees; in the second program (2018), FIT kits were mailed only to enrollees who opted in after an outreach phone call. Participants in this observational study included dual-eligible Medicaid/Medicare enrollees who were aged 50 to 75 years and were due for CRC screening (1799 in 2016 and 1906 in 2018). Six-month FIT completion rates, implementation outcomes (eg, mailed FITs sent and reminders attempted), and program-related health plan costs for each program are described. RESULTS: