The classic candidate for a transrectal ultrasonography (TRUS) evaluation has semen analysis findings consistent with complete distal ejaculatory obstruction, including low ejaculate volume (usually less than 1.5 ml), azoospermia, low pH (less than7), and absence of fructose. In most cases, TRUS can be performed as an outpatient procedure without the need for anesthesia. In order to understand the normal and pathological appearance of the ejaculatory structures on TRUS, it is important to appreciate their anatomic relationships and embryological origins. Traditionally, vasography after vasopuncture was used to evaluate the patency of the ejaculatory ducts. The types of pathologies found on a TRUS evaluation include agenesis or hypoplasia of urogenital structures, cysts, dilatations, calcifications, and stones. Distal ejaculatory duct obstruction (EDO) is strongly suspected in case of azoospermia in which TRUS reveals dilated seminal vesicles with an anteroposterior length greater than 15 mm, or ejaculatory ducts with diameter greater than 2.3 mm.