Uterine fibroids are the most common tumours presenting in women. The pathophysiology of fibroids is poorly understood, but disordered angiogenesis and altered smooth muscle cell proliferation are believed to play a role. In this review, current knowledge of both of these processes will be summarized. Differences between 'normal' adjacent myometrium and fibroid tumours within the same uterus are outlined. Exploiting these differences represents one of the best opportunities for the development of medical treatments that target fibroid tissue selectively.