The work analyzes the phenomenon of the professional accidents in the Policlinico S. Matteo in Pavia, in the quadrenium 1995-1998 to appraise the effects of the application of the D. Lgs 626/94. The obtained data highlight an aggregative diminution of the number of accidents in the biennium 1997-1998 in comparison with the previous biennium 1995-1996. The reduction of the phenomenon of professional accidents is linked substantially with a diminution of the number of accidents with biologic risk. In the quadrennium considered no case of serum conversion has been recorded. It doesn't result significantly altered the number of events of professional accidents linked with the manual handling of loads and with different traumatisms without biological risk. It is highlighted the necessity of more and more close collaboration between the operators of the prevention and the workers.