The addition of pulsed and color Doppler has greatly added to the diagnostic potential for obstetric and gynecologic ultrasound. In addition to improved morphologic detail inherent in the use of EVUS, new information is available on perfusion and the physiologic changes associated with the menstrual cycle and early pregnancy. The absence of luteal flow strongly predicts unsuccessful pregnancy outcome in patients undergoing therapy for infertility. This introduces the possibility of more economic use of expensive treatments. Later in pregnancy, DCI aids in the efficient and accurate performance of Doppler spectral sampling and contributes to the evaluation of structural and functional abnormalities of the fetus, umbilical cord, and placenta. Applications in the evaluation of patients with suspected ectopic pregnancy, incomplete abortion, and pseudosac are welcome additions for clinical problems that currently result in many malpractice suits. Finally, the recognition of neovascular flow, especially in the ovary, raises hope for improved and earlier diagnosis of ovarian cancer.