Lutenized unruptured follicle syndrome (LUFS) is a subtle cause of infertility LUFS. A Luteal phase defect has been implicated as a cause of infertility in 32.6% of infertile women s considered as one of the Luteal phase dysfunction. Ultrasound (transvaginal TVS) has been demonstrated to be the method of choice for diagnosing LUF. This study described use of TVS in diagnosing LUFS and also the role of using pulsed Doppler in describing the different arterial and venous vascular indices in both follicular and luteal phases in the studied functional groups. LUF cycles showed a luteal vascular deficit seen in the luteal phase by Doppler velocimetry. Mid-luteal phase progesterone level is the only hormonal parameter that correlated with maximum luteal phase venous velocity. This makes using color Doppler and serum progesterone useful as a non-invasive tests to evaluate and predict luteal dysfunctions.