Adenomyosis is a common condition characterized by invasion of endometrium into the uterine muscle tissue. This results in myometrial hypertrophy and hyperplasia around the ectopic endometrial glands. The most frequent symptoms associated with the condition are dysmenorrhea, menometrorrhagia and chronic pelvic pain. Recently, infertility has been recognized as being a part of the clinical picture. Until recent years, adenomyosis has primarily been diagnosed in women who are in the late fertile or post fertile years of their life, and the reported prevalence rates varies widely, from 1% to 70%, depending on which population is studied and which diagnostic criteria are used. Clinical diagnosis of adenomyosis is difficult because the signs and symptoms are unspecific. Historically, the diagnosis has been made on hysterectomy specimens. With the advance in medical technology the last few decades, new imaging techniques have been introduced. With transvaginal three-dimensional ultrasound (3D TVU) and magnetic resonance imaging (MRI) it is now possible to make a non-invasive diagnosis of the condition. Treating adenomyosis is a challenge, and hysterectomy has been the only way to treat the condition effectively. There are, however, several alternative options available, such as various types of hormonal therapy, hormone releasing intrauterine devices and minimally invasive procedures that show promising results. A non-invasive diagnosis and treatment that does not require removal of the uterus is especially important for younger women with adenomyosis who wish to preserve their fertility.