This chapter summarizes the diagnostic performance (sensitivity, specificity, positive and negative likelihood ratios) of ultrasound, computer tomography, and magnetic resonance imaging in the diagnosis of various gynecological diseases and tumors. Positron emission tomography is not discussed. Imaging in infertility, in the diagnosis of Mullerian duct anomalies and in gynecological oncology (staging of gynecological cancers, diagnosis of recurrence of gynecological cancer, diagnosis of trophoblastic tumors) is not dealt with. Ultrasound is the first-line imaging method for discrimination between viable intrauterine pregnancy, miscarriage and tubal pregnancy in women with bleeding and/or pain in early pregnancy, for discrimination between benign and malignant adnexal masses and for making a specific diagnosis in adnexal tumors (e.g. dermoid cyst, endometrioma, hemorrhagic corpus luteum, etc.), for diagnosing intracavitary uterine pathology in women with bleeding problems, and for confirming or refuting pelvic pathology in women with pelvic pain. Magnetic resonance imaging can have a role as a secondary test in the diagnosis of adenomyosis, 'deep endometriosis' (e.g. endometriosis in the rectovaginal septum or in the uterosacral ligaments), and in the diagnosis of extremely rare types of ectopic pregnancy (e.g. in the spleen, liver or retroperitoneum).