For many years, medical research has focused on 'hard' end-points, such as survival or time to progression, when evaluating research in cancer clinical trials. However, over recent years more recognition has been given to 'softer' end-points, such as quality of life and treatment satisfaction. In many respects, research into treatment satisfaction is in its early stages of development, but we are already beginning to understand that patients' treatment satisfaction can provide great insights into the management of cancer patients. In our review, we discuss the specific conceptual and methodological issues we face when assessing treatment satisfaction in cancer clinical trials and critically review earlier studies of cancer treatment satisfaction.