OBJECTIVES: We tested the effectiveness of offering home fecal immunochemical tests (FITs) during influenza vaccination clinics to increase colorectal cancer screening (CRCS). METHODS: In a clinical trial at Kaiser Permanente Northern California influenza clinics in Redwood City, Richmond, South San Francisco, Union City, and Fresno, we randomly assigned influenza clinic dates to intervention (FIT offered) or control (FIT not offered) and compared subsequent CRCS activity. RESULTS: Clinic staff provided FITs to 53.9% (1805/3351) of intervention patients aged 50 to 75 years. In the intent-to-treat analysis, 26.9% (900/3351) and 11.7% (336/2884) of intervention and control patients completed an FIT, respectively, within 90 days of vaccination (P = .001). The adjusted odds ratio for completing FIT in the intervention versus the control arm was 2.75 (95% confidence interval = 2.40, 3.16). In the per protocol analysis, 35.4% (648/1830) of patients given FIT and 13.3% (588/4405) of patients not given FIT completed FIT within 90 days of vaccination (P = .001). CONCLUSIONS: This intervention may increase CRCS among those not reached by other forms of CRCS outreach. Future research should include the extent to which these programs can be disseminated and implemented nationally.