Transrectal biopsy of the prostate, because of its directness and simplicity, is utilized by many practicing urologists to obtain prostatic tissue for histologic evaluation. Complications arising from this procedure are primarily of an infectious origin and less commonly of a vascular etiology. We report on the first known patient in whom a large hematoma of the anterior rectal wall with nearly total occlusion of the rectal lumen developed following a transrectal ultrasound-guided biopsy of the prostate. Guidelines to reduce the likelihood of vascular complications following biopsy of the prostate gland for patients consuming medications that may alter normal platelet function or interfere with the various clotting factors are described.