CT-guided fine-needle aspiration biopsy was carried out in 177 patients with proven intra-, retro- or extraperitoneal lesions. This method verified the diagnosis in 89/132 cases (66%) with malignant neoplasia, metastases and recurrent malignant tumors. In 45 patients with benign or inflammatory lesions of the intra- and retroperitoneal space, fine-needle puncture showed a purulent liquid, inflammatory altered cell elements or a positive bacteriological result. The success of CT fine-needle puncture depends mainly on the examiner's experience, the exact localization of the needle, and careful handling of the cytological material. Fine-needle puncture should be applied simultaneously with CT when an undefined space-occupying lesion is present. Unsuccessful sonography is an indication for CT-guided fine-needle puncture.