The search for quality in the health service cannot lead aside the safety of its operators and users, subject to the well defined parameters of Law 626. This study makes a preliminary examination of the accidents occurring in our Health District which comprises three hospitals, 600 beds and 1,800 employees. A total of 172 accidents have been reported. The percentages can be broken down between the various sectors: 73% of accidents involve nurses, 9% involve doctors and 1% administrative personnel. The greatest risk in hemodialysis is the biological factor (through accidental cuts or pricks which account for 67% of the accidents reported) and involves humans (both patients and personnel), monitors and environments as the sources of pathogens. The most frequently isolated germs are E. coli and Pseudomonas. It has been shown that prevention is above all based on the accuracy with which procedures are followed. The risk of hepatitis C has not yet been resolved, as is affinned in a review reported in the study. The HIV risk gives the greatest cause for concern, even if only 0.2% after exposure compared to 15-36 for HbsAg. Compliance with universal rules for prevention and post-exposure procedures provides an adequate guarantee for prevention.