Background: Penile echo-color Doppler ultrasound (PCDU) is the gold standard for the diagnosis of arterial erectile dysfunction (ED). Its reliability in patients with anxiety was questioned, due to false-positive results. Aim: To assess the penile hemodynamic response to intracavernous injection (ICI) of alprostadil in patients with anxiety-related ED. Methods: Patients with non-organic ED and a 5-item International Index of Erectile Function (IIEF-5) score ranging between 5 and 7 were enrolled. They were asked to compile the 7-item Generalized Anxiety Disorder (GAD-7) questionnaire to assess the degree of anxiety and were divided according to the GAD-7 score in Group 1 with minimal level of anxiety (n = 20), Group 2 with mild anxiety (n = 20), Group 3 with moderate anxiety (n = 20), and Group 4 with severe anxiety (n = 20). Peak systolic velocity (PSV) and the end-diastolic velocity (EDV) were sampled in all patients, through PCDU in the flaccid state, and 5, 10, 15, and 20 min after ICI of alprostadil at the standard dose of 10 μg. Results: In penile flaccidity, the patients showed a mean PSV of 8.0 ± 4.0 cm/s. The degree of anxiety was found to significantly influence both PSV and EDV at all assessed time-points. Particularly, it was negatively associated with the PSV at time 5 (r = −0.9, p < 0.01), 10 (r = −0.9, p < 0.01), 15 (r = −0.9, p < 0.01), and 20 (r = −0.7, p < 0.01) minutes, and positively with the EDV at time 5 (r = 0.7, p < 0.01), 10 (r = 0.6, p < 0.01), 15 (r = 0.5, p < 0.01), and 20 (r = 0.3, p < 0.01) minutes. Although all patients showed a mean dynamic PSV > 25 cm/s (which excluded an arterial ED according to the current guidelines), a peculiar hemodynamic pattern was found in patients with severe anxiety. In these patients, normal PSV values were reached only after 20 min from ICI, suggesting a “late-responder” profile. Conclusion: If further studies confirm the existence of a distinct hemodynamic profile in patients with severe anxiety, sampling the PSV and the EDV values could be proposed, for detecting patients with severe anxiety-related ED. Dynamic PCDU could be considered an accurate diagnostic test in patients with non-organic ED, since zero false-positive results were found in the present study. PSV in the flaccid state is not able to discriminate between arterial- or non-organic ED.