The article analyses the results of 104 biopsies which were carried out in 84 patients with different diseases of the organs of thoracic (50) or abdominal (16) cavities, postperitoneal space (32), bones and soft tissues (6). Positive results were obtained in 67 cases, negative--in 26, false-negative--in 11. The specificity was 70.3%, sensitivity--100%, authenticity--64.4%. The authors make a conclusion that the results and authenticity of biopsies depend on such factors as the proper organ to be punctured, character and structure of the affection, its location, volume and spreading, as well as the type of needles to be used.