In soft tissue sarcomas, advances in pathological techniques, including immunohistochemistry, cytogenetics, and molecular genetics, have improved diagnostic accuracy, confirmed or clarified interrelationships between tumor subtypes, and revealed mechanisms of tumorigenesis. Many sarcomas are associated with abnormalities of tumor-suppressor genes, and several types have been found to have specific chromosomal translocations. These data and correlative clinicopathologic studies, although confirming many traditional pathological views, enable refinement or reassessment of terminology and classification of some small round cell, spindle cell, pleomorphic, and lipogenic tumors. New factors are emerging for prediction of tumor behavior, which might ultimately relate to therapy once a wider range of treatment options becomes available. This article reviews these current aspects of sarcoma pathology.