A majority of cancer diagnoses and deaths occur in patients age ≥ 65 years. With the aging of the US population, the number of older adults with cancer will grow. Although the coming wave of older patients with cancer was anticipated in the early 1980s, when the need for more research on the cancer-aging interface was recognized, many knowledge gaps remain when it comes to treating older and/or frailer patients with cancer. Relatively little is known about the best way to balance the risks and benefits of existing cancer therapies in older patients; however, these patients continue to be underrepresented in clinical trials. Furthermore, the available clinical trials often do not include end points pertinent to the older adult population, such as preservation of function, cognition, and independence. As part of its ongoing effort to advance research in the field of geriatric oncology, the Cancer and Aging Research Group held a conference in November 2012 in collaboration with the National Cancer Institute, the National Institute on Aging, and the Alliance for Clinical Trials in Oncology. The goal was to develop recommendations and establish research guidelines for the design and implementation of therapeutic clinical trials for older and/or frail adults. The conference sought to identify knowledge gaps in cancer clinical trials for older adults and propose clinical trial designs to fill these gaps. The ultimate goal of this conference series is to develop research that will lead to evidence-based care for older and/or frail adults with cancer.