The objective of this study was to evaluate the sensitivity and specificity of percutaneous core-needle biopsy of enlarged lymph nodes in the diagnosis and subclassification of malignant lymphomas. In a 1-year period 158 image-guided percutaneous core-needle biopsies of enlarged lymph nodes were performed on 149 consecutive patients using a Tru-cut needle fired by a biopsy gun. In 135 cases the biopsy findings could be confirmed by histologic examination of additional tissue samples (n = 59) or by correlation with the patient's clinical and radiologic course (n = 76). The final diagnoses were malignant lymphoma in 65 cases, leukemic nodal infiltration in 2, nodal metastases from a solid tumor in 37 and benign changes or no evidence of malignancy in 31 cases. The core-needle biopsies correctly diagnosed 58 of 65 malignant lymphomas, corresponding to a sensitivity of 89% and a specificity of 97%. Fifty-five of the 58 (95%) correctly diagnosed malignant lymphomas could be subclassified on the basis of the core-needle biopsy. Image-guided core-needle biopsy of enlarged lymph nodes with a Tru-cut needle is a useful method for the diagnosis and subclassification of malignant lymphomas.