Fibroids are a prevalent disorder occurring in at least half of American reproductive-age women. In general, the incidence and size increases with age. Most women never attribute or report any symptoms from their fibroids, and because of this the actual contribution of disease to symptoms of pelvic pain,menstrual symptoms, and infertility is poorly understood. The presence of fibroids can lead to multiple and disabling difficulties. Fibroids may cause pain and menstrual bleeding to the point of anemia. Fibroids clearly reduce fertility,increase preterm labor and delivery, and markedly increase the risk for cesarean delivery. Because the incidence varies according to population of interest, fibroids may explain some health disparities in different populations. For example,African Americans have a relatively poor outcome with assisted reproductive techniques compared with whites. Controlling for fibroid disease may explain this disparity, at least in part. Fibroids represent a tremendous public health burden on women and economic cost on society. Strategies to prevent, limit growth, and treat nonsurgically are needed. Fundamental and significant questions remain about fibroid disease,such as whether different clinical disease phenotypes (multiple versus single leiomyomas) contribute equally to symptoms and possess an equal likelihood of disease progression. For epidemiologic assessment of disease, a scoring system is urgently needed. Well-designed, controlled, prospective studies are still needed to define the natural history and correlate the presence of disease with symptomatology in women.