Fecal immunochemical testing is the most commonly used method for colorectal cancer screening worldwide. However, its effectiveness is frequently undermined by failure to obtain follow-up colonoscopy after positive test results. To evaluate interventions to improve rates of follow-up colonoscopy for adults after a positive result on a fecal test (guaiac or immunochemical). English-language studies from the Cochrane Central Register of Controlled Trials, PubMed, and Embase from database inception through June 2017. Randomized and nonrandomized studies reporting an intervention for colonoscopy follow-up of asymptomatic adults with positive fecal test results. Two reviewers independently extracted data and ranked study quality; 2 rated overall strength of evidence for each category of study type. Twenty-three studies were eligible for analysis, including 7 randomized and 16 nonrandomized studies. Three were at low risk of bias. Eleven studies described patient-level interventions (changes to invitation, provision of results or follow-up appointments, and patient navigators), 5 provider-level interventions (reminders or performance data), and 7 system-level interventions (automated referral, precolonoscopy telephone calls, patient registries, and quality improvement efforts). Moderate evidence supported patient navigators and provider reminders or performance data. Evidence for system-level interventions was low. Seventeen studies reported the proportion of test-positive patients who completed colonoscopy compared with a control population, with absolute differences of -7.4 percentage points (95% CI, -19 to 4.3 percentage points) to 25 percentage points (CI, 14 to 35 percentage points). More than half of studies were at high or very high risk of bias; heterogeneous study designs and characteristics precluded meta-analysis. Patient navigators and giving providers reminders or performance data may help improve colonoscopy rates of asymptomatic adults with positive fecal blood test results. Current evidence about useful system-level interventions is scant and insufficient. National Cancer Institute. (PROSPERO: CRD42016048286).