Purpose: Various diagnostic tools have been developed to diagnose and differentiate the causes of female sexual dysfunction. In this study, we used laser Doppler flowmetry to measure the genital blood flow and analyzed its usefulness as a diagnostic tool in patients with sexual dysfunctions. Materials and Methods: We enrolled 50 female patients with sexual difficulties(45.8+/-9.8 years old). Ten sexually healthy women were enrolled as a control group. We measured the superficial blood flow of the clitoral glans, vestibule, and anterior wall of the vagina using laser Doppler flowmetry(Periflux 5000, Permed AB, Sweden), and compared these measurements with blood flow measured in response to sexual stimulation induced by an erotic film. Medical and personal histories, physical examinations, and self-reporting questionnaires were taken from the patients for classifying their sexual problems. Results: The patients complained of problems with desire(46 patients, 92%), arousal(41, 82%), orgasm(49, 98%), pain(10, 20%), and satisfaction(32, 64%). Most patients had more than one problem. In patients with sexual dysfunction, baseline blood flows at all measuring sites were significantly lower than in the control group(p<0.05). After the sexual stimulation, the blood flows of the glans, vestibule, and anterior vaginal wall were significantly increased(p<0.0001). In the groups with desire and arousal problems, blood flow changes were significantly less than in the control group. Conclusions: Laser Doppler flowmetry can provide very useful information on whether patients have hemodynamic-based sexual problems. We can approach the causes of sexual difficulties, particularly sexual desire or arousal problems, using this novel technological instrument.