Colorectal cancer screening uptake is low, particularly among individuals enrolled in Medicaid. To the authors' knowledge, little is known regarding the effectiveness of direct-to-member outreach by Medicaid health insurance plans to raise colorectal cancer screening use, nor how best to deliver such outreach. BeneFIT is a hybrid implementation-effectiveness study of 2 program models that health plans developed for a mailed fecal immunochemical test (FIT) intervention. The programs differed with regard to whether they used a centralized approach (Health Plan Washington) or collaborated with health centers (Health Plan Oregon). The primary implementation outcome of the current study was the percentage of eligible enrollees to whom the plans delivered each intervention component. The primary effectiveness outcome was the rate of FIT completion within 6 months of mailing of the introductory letter. The health plans identified 12,000 eligible enrollees (8551 in Health Plan Washington and 3449 in Health Plan Oregon). Health Plan Washington mailed an introductory letter and FIT kit to 8551 enrollees (100%) and delivered a reminder call to 839 (10.3% of the 8132 attempted). Health Plan Oregon mailed an introductory letter, and a letter and FIT kit plus a reminder postcard to 2812 enrollees (81.5%) and 2650 enrollees (76.8%), respectively. FIT completion rates were 18.2% (1557 of 8551 enrollees) in Health Plan Washington. In Health Plan Oregon, completion rates were 17.4% (488 of 2812 enrollees) among enrollees who were mailed an introductory letter and 18.3% (484 of 2650 enrollees) among enrollees who also were mailed a FIT kit plus reminder postcard. The implementation of mailed FIT outreach by health plans may be effective and could reach many individuals at risk of developing colorectal cancer. © 2019 The Authors. Cancer published by Wiley Periodicals, Inc. on behalf of American Cancer Society.