Gleason grading system is the accepted grading system throughout the world, despite its inception almost 40 years ago. Initially Gleason intended to classify carcinomas into five patterns. In years 1974 and 1977 additional comments concerning the aplication of the Gleason system were provided. Certain aspects of the original Gleason system are interpreted differenty in today's practice. The medicine in general and prostate carcinoma in spesific has changed dramatically since the late 19- 60's. The new screening methods (PSA), the concept of obtaining more extensive prostate tissue by sextant needle biopsies, radical prostatectomy operations, new adenocarcinoma variants made it necessary to make a new concensus about Gleason System. The authors of the Gleason grading survey convened a group of urologic pathologists at the 2005 United States and Canadian Academy Meeting in San Antonio in an attemp to achieve consensus in conrotroversial areas relating to the Gleason grading system.