In the long-term there is biochemical evidence of recurrent prostate carcinoma in ≈ 40% of patients after radical prostatectomy (RP). Detecting the site of recurrence (local vs distant) is critical for defining the optimum treatment. Pathological and clinical variables, e.g. Gleason score, involvement of seminal vesicles or lymph nodes, margin status at surgery, and especially the timing and pattern of prostate-specific antigen (PSA) recurrence, may help to predict the site of relapse. Transrectal ultrasonography (TRUS) of the prostatic fossa in association with TRUS-guided needle biopsy is considered more sensitive than a digital rectal examination for detecting local recurrence, especially if PSA levels are low. Although it cannot detect minimal tumour mass at very low PSA levels (<1 ng/mL) TRUS biopsy is presently the most sensitive method for detecting local recurrence. Nevertheless, the conclusive role of biopsy of the vesico-urethral anastomosis remains unclear. However, 111In-capromab pendetide scintigraphy and [11C]-choline tomography (which are better than conventional imaging for detecting metastatic tumour), have low detection rates for local disease and are considered complementary to TRUS in this setting. Patients with a high PSA after RP may be managed with external beam salvage radiotherapy. An initial PSA of < 1 ng/mL, Gleason score < 8 and radiation dose of 66–70 Gy seem to be key factors in determining success. Although a positive TRUS anastomotic biopsy may predict a better outcome after radiation therapy, the need to take a biopsy in the event of PSA failure remains under investigation. The value of salvage radiation to the prostatic bed for PSA-only progression after RP remains in question.