Fifty-one CT-guided percutaneous fine-needle aspiration biopsies (PFNAB) were performed on 46 consecutive patients over 15 months. Cytologies were obtained to identify primary or secondary malignancy in the abdomen, pelvis, retroperitoneum, bone, and paraspinal region. Adequate cytologic material was obtained in 50 of 51 biopsies. There were 29 true-positive, 0 false-positive, 12 true-negative, and two false-negative cases with an overall accuracy rate of 95 percent. There was one minor complication, mesenteric hemorrhage, which did not require transfusion. Fifteen of the 51 biopsies were performed on outpatients. The procedure is an accurate, safe, and cost-effective nonsurgical means of diagnosing primary or secondary malignancy.