By Color-Doppler ultrasound it's possible to visualize urine flow from ureter into the bladder. Aim of the study was to image these ureteral jets in patients with benign prostatic hyperplasia (BPH) before and after therapy. Seven patients were studied, whose age ranged from 52 to 69 years; they were not affected by methabolic, hepatic, renal diseases and by prostate inflammation. A duplex scanner (Toshiba SSA 270 A) with a convex probe of 3.5 MHz was used. A transabdominal ultrasound study was performed, measuring prostatic volume and imaging ureteral jet before and along a treatment (at four months intervals) with Finasteride 5 mg/die (Finastid, Neopharmed) and at the end of treatment. We found that the mean velocity of jets in patient affected by was higher than in healthy subjects (80 cm/sec vs 60 cm/sec) bur during treatment it decreased along with symptom improvements and decreasing volume at US. We concluded that analysis of ureteral jets with Color-Doppler P.W. may add useful informations to real-time us in the study of patients affected by BPH undergoing treatment with Finasteride.