Colorectal cancer screening is one of the few cancer screenings with an “A” rating from the US Preventive Services Task Force, meaning that the procedure confers a substantial health benefit. However, 40 percent of people who should receive colorectal cancer screenings do not receive them. Colonoscopies are the most thorough method of screening because they allow physicians to view the entire length of the colon and remove polyps as needed. Billing methods that distinguish between screening and therapeutic procedures have kept expected colonoscopy costs high. However, the Affordable Care Act partially closed the so-called colonoscopy loophole and reduced expected out-of-pocket expenses for all Medicare beneficiaries. Using data from the Behavioral Risk Factor Surveillance System, we found that annual colonoscopy rates among men ages 66–75 increased significantly (by 4.0 percentage points) after the Affordable Care Act policy change, and we found some evidence of even larger increases among socioeconomically disadvantaged men. We found no significant increases among women, a result that may be explained by health behavior and other factors and that requires further study. Our research indicates that cost may be an important barrier to colorectal cancer screening, at least among men, and that making further policy changes to close remaining loopholes may improve screening rates.