Clinical trials are essential for developing new and effective treatments and improving patient quality of life; however, many trials cannot answer their primary research questions because they fall short of their recruitment goals. This article reports the results of formative research conducted in two populations, the public and primary care physicians, to identify messages that may raise awareness and increase interest in clinical trials and be used in a national communication campaign. Results suggested that participants were primarily motivated to participate in clinical trials out of a self-interest to help themselves first. Messages illustrated that current treatments were tested via clinical trials, helped normalize trials as routine practices, and reduced concerns over trying something new first. Participants wanted messages that portray trials as state-of-the-art choices that offer some hope, show people like themselves, and are described in a clear, concise manner with actionable steps for them to take. The study revealed some differences in message salience, with healthy audiences exhibiting lower levels of interest. Our results suggest that targeted messages are needed, and that communication with primary health-care providers is an important and necessary component in raising patient awareness of the importance of clinical trials.