Transrectal ultrasonography (TRUS) is now widely used in urological practice and has a place for selecting patients undergoing surgery (TURP vs. Open), performing guided biopsy of digitally abnormal findings or imaging of the prostate in case of elevated prostate-specific antigen (PSA). The technique is advantageous in monitoring therapy (medical treatment for benign prostatic hyperplasia (BPH) or follow-up of prostate cancer). It is the best available imaging modality in the follow-up of patients after external or interstitial irradiation, certainly if TRUS is combined with guided biopsies. TRUS can be used in interstitial irradiation for an exact placement of seeds or needles. The role of TRUS in staging prostate cancer has not been defined, although staging is improved with TRUS. Improvement of early detection of prostate cancer using TRUS is only marginal and digital rectal examination combined with PSA is generally accepted as ‘screening’ investigations. Imaging of the prostate and the seminal vesicles has its place in the diagnostic workup for infertility and prostatitis.