Purpose: To determine whether an extended sector biopsy of the prostate will increase the detection of prostate cancer, without causing an increase in morbidity. Materials and Methods: A total of 74 men with a mean age of 62.3 years (46-98 years) who either had an elevated PSA or an abnormal digital rectal exam underwent a transrectal ultrasound guided needle biopsy. Beginning on 7/1/98, an extended sector biopsy technique was performed on 74 patients by one urologist (RRB). Each transrectal ultrasound guided needle biopsy included 12 total cores (normal sextant biopsy, 2 in each peripheral zone, and 2 in the transition zone). We retrospectively reviewed the biopsy results for the location of cancer. PSA data and morbidity of the procedures were reviewed. Results: Of 74 total patients, 40 (54.1%) were positive for adenocarcinoma of the prostate. There were 10 positive results detected only in the additional zones. If one looks at the total number of cancers detected (40), then 10/40 (25%) of the cancers detected were found in the additional regions only or in 13.5% of all patients biopsied. Of the 10 patients with sector only prostate cancer, 8 were detected in the peripheral zone, 1 in the transition zone and 1 in both zones. All 10 patients had a Gleason pattern score 3+3=6 or 4+3=7. There were no atypical or PIN cores found in the sector zones only. PSA ranged from 1.2-142 (median 6.0 ng/ml). The median PSA was 6.2 ng/ml in all patients found to have cancer, and 6.0 ng/ml in the cancers detected only in the additional zones. There was 1 (1.4%) complication of urinary retention and fever. Conclusion: Our study suggests that an extensive sector biopsy may increase the detection of prostate cancer by 13.5% over a routine sextant biopsy, without demonstrable serious morbidity.