Objectives. In 2013 the International Society for Sexual Medicine(ISSM) published the guidelines regarding the standard operating procedure (SOP) for penile duplex Doppler ultrasound (PDDU). Although ISSM-SOP have given important strides in reducing interobserver variability in PDDU by procedural protocol and parameters these guidelines do not address the anatomic location along the penis at which hemodynamic measurements have to be done. In our opinion a “double sampling” may be interesting to detect the arteriogenic or venogenic nature of the erectile dysfunction (ED). In particular sampling measurements at the “crus” (at the level of the peno-scrotal junction) may be significative for detection of veno-occlusive dysfunction (VOD),whereas an evaluation at “mid penis” (1/2 distance between peno-scrotal junction and coronal sulcus), may be useful to diagnose an arterial insufficiency (AI). Material and Methods. We evalued 90 men, mean age 56.3, affected with ED of medium degree, responder to PDE5-I that urdergone to PDDU and also responder after pharmacologic intracavernosal injection (PII)of prostaglandin E1 20 mcg, with rigid erection and normal maintenance. We moreover evalued 90 men in youthful age (mean 35.2), in absence of vascular risk factors, no responder to PDE5-I that undergone to PDDU by PII at high dosage (bimix: prostaglandin E1 20 mcg, papaverine 20 mg). Results. In the first pool the sampling at “mid penis” resulted significative for arterial insuffciency (AI) in 81% (73), in presence of normal or borderline end diastolic velocity (EDV). Sampling at the “crus” resulted negative for VOD in 90% (81). In the second pool, 66.6% (60) resulted responder with rigid erection and normal maintenance in presence of normal hemodynamic parameters: peak systolic velocity (PSV) and end diastolic velocity (EDV) both at the “crus” and at “mid penis” sampling. 33.4% (30) responded with a semirigid erection and manifested a constant deficit of maintenance; at the “crus”and at “mid penis” the hemodynamic arterial parameters resulted normal. At the “crus” the EDV resulted significantly augmented (VOD index) in 96.6% (29); at “mid penis” augmented EDV was founded in 50% (15). Conclusions. These observational data would be able to confirm the utility of a routinary “double sampling” procedure, at the “crus” and at “md penis”, during PDDU in order to better distinguish between VOD or AI or in any case to be useful to stimulate a future more precise standardization in execution of PDDU examination.