Adenomyosis is a relatively frequent finding in series of hysterectomies performed for menorrhagia and dysmenorrhea. Evident selection biases of the available studies on adenomyosis have always limited the possibilities of defining the real clinical importance of the condition. Until now the only certain diagnoses have been made by histopathologists on uteri removed at surgery, but recently various sufficiently accurate techniques have been suggested which allow diagnosis on the uterus in situ. With the these methods it might be possible to obtain correct information on the epidemiologic characteristics of adenomyosis and to clarify whether it has a pathogenic role in unexplained ovulatory menorrhagia and juvenile dysmenorrhea. Furthermore, resectoscopic treatment has been proposed in some mild forms of adenomyosis to avoid hysterectomy, whereas it seems improbable that medical treatment can offer a definitive solution. The adoption of standard histologic criteria for adenomyosis seems important. Until this is done, it will be difficult to establish whether adenomyosis is really a disease or merely a paraphysiologic condition.