There has been much research on the subject of environmentally sustainable design (ESD), with emerging techniques and technologies improving rapidly and informing sustainability higher education teaching to architects and prospective architects. By examining the success of sustainable designs using post occupancy evaluations, architectural practices might also increase their knowledge of sustainable building practice. Post occupancy evaluations could be useful for improving the designs of future buildings and the design processes that generated them. This paper aims to evaluate these claims by asking: "Do sustainable design practices use the feedback gained from post occupancy evaluations?," "How does the feedback refine the design process?," "How is the information gained in these evaluations absorbed within the firm\u27s design practices?," and, "Does the size of a practice impact on its implementation anddissemination of POE?" This paper investigates the questions posed above through the questioning of architectural practices that have gained a reputation for environmentally sustainable design by having a strong sustainable design philosophy and/or by being recognised for this by winning a sustainability design award. The interviewed practices will have provided some form of post occupancy evaluation as a service or employed them to add to their own knowledge.<br /