Ultrasound imaging and ultrasound guided transrectal core biopsies were performed in 251 consecutive men with abnormal prostates on digital rectal examination. A hypoechoic defect on ultrasound was identified in 227 of 251 patients (90 per cent) corresponding to the area of palpable nodularity or abnormal firmness. A mean of 6.25 biopsies were obtained per patient using a commercially available spring-loaded gun. Biopsies were positive for cancer in 165 of the 251 prostates (66 per cent). Palpable nodules more often were hypoechoic and more often contained cancer than less distinct areas of abnormal firmness on digital examination. Among the clinical stages B1, B2 and B3 nodules 70, 76 and 88 per cent, respectively, were positive for cancer, as were 100 per cent of the clinical stage C prostates. Of 77 abnormally firm, nonnodular prostates 36 per cent were positive for cancer. Random biopsy of the contralateral normal lobe in 56 men with clinical stage B1 or B2 nodules showed cancer present contralaterally in 42 and 60 per cent, respectively; 20 per cent had positive biopsies despite a contralateral isoechoic ultrasound. In 78 patients with prior digitally guided biopsies, ultrasound guided biopsies confirmed previously diagnosed cancers in 94 per cent. However, in 23 of 43 patients (53 per cent) with previous negative digitally guided biopsies, ultrasound guided biopsies made the new diagnosis of cancer. Complications, including post-biopsy fever and bleeding, occurred in 6 of 251 patients (2.4 per cent). The combination of the new spring-loaded biopsy guns and transrectal ultrasound guidance of biopsies provides the urologist with a tool that allows multiple prostate cores to be obtained safely and painlessly, reducing the sampling error and increasing the accuracy in diagnosing prostate cancer in the man with a palpable abnormality of the prostate.