Heparanase is an endo-beta-glucuronidase that cleavages intradisaccharide heparan sulfate linkage, and has been involved with degradation of cellular surface and extracellular matrix heparan sulfate proteoglycans (Cohen I.R., et al. 1994). Increased expression of heparanase is involved with tumor development (Hullet M.D. et al. 1999; Vlodavsky I. et al. 2000). The biological role of heparanase in vivo seems to be involved with: 1) tumor cell invasion and metastasis through vessels, basement membrane and extracellular matrix; 2) activate growth factors that can promote cell proliferation and angiogenesis (Vlodavsky et al., 1990). The objective of this work was to evaluate heparanase expression in adult kidney carcinomas, comparing with transition tissues and non neoplasic tissues (normal tissues), originated from the same patient. It was obtained (carcinoma, transition and non neoplasic tissues) from 25 patients submitted to surgery, including 16 males and 9 females with an average of age 59 years old. These patients were submitted to surgery in 7 differents hospitals: Hospital and Maternidade Santa Maria Cruz Azul, Hospital Itamaraty, Hospital Santa Marcelina, Hospital Estadual Mario Covas, Hospital Santa Cruz, Hospital and Maternidade Brasil and Hospital Anchieta in São Bernardo do Campo. The extraction of total RNA was obtained using TRIZOL^® (Life Technologies), and heparanase expression was analyzed by semi-quantitative RT-PCR (Super Script II - Invitrogen^® and Master Mix 2X - Promega^®). The heparanase expression was compared with glyceraldehyde-3-phosphate-dehydrogenase (GAPDH) expression. The results had shown a higher heparanase expression at tumor tissues comparing with transition and non neoplasic tissues. However, statistical analysis has been doing in order to validate the difference in heparanase expression levels at carcinoma kidney. The profile of heparanase expression at kidney tissues led us to conclude that this enzyme could be useful as a potential marker of tumor prognosis in adult kidney neoplasia. Supported by FAPESP, CAPES, CNPq and NEPAS.