: When may a physician legitimately offer enrollment in a randomized clinical trial (RCT) to her patient? Two answers to this question have had a profound impact on the research ethics literature. Equipoise, as originated by Charles Fried, which we term Fried's equipoise (FE), stipulates that a physician may offer trial enrollment to her patient only when the physician is genuinely uncertain as to the preferred treatment. Clinical equipoise (CE), originated by Benjamin Freedman, requires that there exist a state of (...) honest, professional disagreement in the community of expert practitioners as to the preferred treatment. FE and CE are widely understood as competing concepts. We argue that FE and CE offer separable and, in themselves, incomplete justifications for the conduct of clinical trials. FE articulates conditions under which the fiduciary duties of physician to patient may be upheld in the conduct of research. CE sets out a standard for the social approval of research by institutional review boards. Viewed in this way, FE and CE are not necessarily competing notions, but rather address complementary moral concerns. (shrink)