The discovery of ghrelin and its role in human metabolism has promoted significant research and advances in the study of obesity and other weight-related disorders. Ghrelin is relevant to many disorders of metabolism and weight such as obesity, cachexia, Prader-Willi Syndrome (PWS), and Anorexia Nervosa (AN), and its role in the pathophysiology differs. The changes observed in ghrelin physiology in these disorders shed light on the overall role of ghrelin in human metabolism and growth. The purpose of this review is to summarize the existing literature on ghrelin and some disorders of metabolism and growth. The disorders that will be discussed include obesity, cachexia, PWS, and AN. Within each disorder we will review relevant ghrelin physiology, recent studies, and potential modes of intervention with ghrelin analogues.