The aim of this work was to establish if duplex parameters obtained for the assessment of the patency of cavernosal arteries in the penile flaccid state can give sufficient clinical information without the use of intracavernosal injection of vasodilatory drugs. We assessed Diameter of both cavernosal arteries, PSV, EDV, RI, and acceleration time in both cavernosal arteries in 100 unselected patients with erectile dysfunction before and after injection of 30 mg papaverine +1 mg phentolamine mixture, theses parameters were also assessed in 50 normal individuals with no erectile problems without use of intracavernosal injection (as control) theses control group was classified into 4 age subgroups. The results of the study can be summarized as follows: (1) There was a significant relationship between basal PSV and dynamic PSV and between basal acceleration and dynamic PSV (P value 0.039, 0.036 respectively);(2) A basal PSV≥12.62 cm/sec was predictive of a dynamic PSV≥30 cm/sec in 42/76(76.4%) of the patients, while a basal PSV <12.6 cm/sec was predictive of dynamic PSV<30 cm/sec in 11/24 (45.8%) of patients with overall accuracy 53%;(3) A basal acceleration ≥2.28 m/sec² was predictive of dynamic PSV≥30 cm/sec in 44/49 (89.8%) of patients, while a basal acceleration <2.28 m/sec² was predictive of a dynamic PSV<30 cm/sec in 19/51 (37.3%) of patients with overall accuracy 63%.(4) After the age of 50, there is significant reduction at that age in potent males. In conclusion, measurement of basal PSV and basal acceleration is highly specific test but with poor specificity and poor overall accuracy and so cannot replace the use of intracavernosal injection in the assessment of cavernosal arterial condition.