The morphology of seminal vesicles is precisely evaluable with the transrectal approach, especially with end-fire probe and an oblique scan. Standard criteria, divided into conventional and unconventional, are used to evaluate the modifications of ultrasound imaging of seminal vesicles. The most common alteration is dilation, especially due to obstruction caused by chronic inflammation in the case of prostatitis. Transrectal ultrasound of seminal vesicles is indicated in hematospermia, infertility, and perineal pain. We reviewed the pattern of invasion by prostate cancer. The absence of one or both seminal vesicles is highly suspicious for anomalies of the urinary tract on the same side, which has to be examined.