Clear cell sarcoma of the kidney (Light microscopic study of 8 cases and electronmicroscopic study of 2 cases). The eight clear cell sarcoma cases of kidney we studied constituted 7,3 % of primary renal tumors of childhood. The mean age was 15,6 months and male to female ratio was 3 to 1. Although clinical follow-up was not possible in all cases, lymph node metastasis in one case, liver metastasis in one case and brain-spine metastasis in another case were seen. In addition to the classical features microscopically seen in these tumors, epitheloid trabecular pattern, areas like neurolemmoma, fibrozis and stromal hyanilisation, cystic spaces and angiectasies were seen in various ratios in our cases. Ultrastructural findings suggestive of mesenchymal tumor were found. According to our light and electronmicroscopic findings we think the tumor is a distinct entity other than Wilms' tumor.