The quality control scheme in use at the Department of Anatomic Pathology of the University of Bologna-Bellaria Hospital Since 1993 a quality assurance (QA) scheme has been set up in our Department, modified from the protocol in use at the Department of Pathology of Yale University and published by J. Rosai in his textbook. A QA committee has been appointed and each member is responsible for a specific branch of the total workload; the areas involved are: 1. review of frozen section diagnoses with the final diagnoses 2. randomized review of biopsies (1:25) 3. quality control of cytological cases 4. quality control of specimen adequacy 5. quality control of immunohistochemistry and in situ Hybridization 6. quality control of the cytogenetics laboratory 7. quality control of autopsies All data collected from january 1996 to february 1999 have been reviewed and analyzed in order to provide references for other laboratories and for the purpose of monitoring our laboratory' performance.