In connection with a health control study of 2,400 men for early detection of prostate cancer the authors have compared fine-needle aspiration biopsy using a new automatic fine-needle gun with histological cores obtained by the Biopty gun. Both procedures were ultrasonically guided. Prostate cancer was found in 62 patients and in 46 of these both biopsy methods were used on the same occasion. There was no essential difference in sensitivity between the two methods. The authors recommend fine-needle aspiration biopsy as the primary method but regard the histological core technique as a valuable supplement.