The objective of this study in Rochester, NY was to determine clinicians' knowledge of the Colorado Medical Society Guidelines (CMSG) on return to contact sports after a concussion. A survey was mailed to 1,140 pediatric, family practice, and emergency physicians, as well as 302 pediatric and family practice nurse practitioners in the Rochester, NY, area. Participants were given 3 hypothetical concussion scenarios and asked to pick 1 of 4 multiple-choice time intervals for when they would advise return to contact sports. Answers were compared with the latest version of the CMSG. The survey response rate was 57%. Only 7.6% responded correctly for Grade 1 concussion scenario, 56% for the Grade 2 scenario, and 28% for the Grade 3 scenario. Only 5.6% listed the CMSG as the source of the return-to-play advice they gave. Thus, respondents' knowledge of the CMSG was low, with few giving return-to-play advice consistent with the CMSG and even fewer acknowledging the CMSG as the source of such advice. Improving the availability of the CMSG may improve clinicians' knowledge and use of these guidelines.