This study presents the cytologic findings of fine-needle aspiration (FNA) in a series of 136 primary soft-tissue tumors. The cytologic appearances of some rare mesenchymal lesions are presented, including the first (to our knowledge) published descriptions of fibrous hamartoma of infancy and myositis ossificans. Fine-needle aspiration showed high diagnostic sensitivity (95%) and specificity (95%) for the determination of malignancy, approaching that obtained with frozen-section interpretation. Problems encountered with the diagnosis of mesenchymal lesions, including nodular fasciitis, Kaposi's sarcoma, and spindle cell lipoma, are discussed. Based on these findings, recommendations for aspiration cytology of soft-tissue tumors are presented.