Nosocomial infections are a great problem in the ICUs and hand washing is the best way to control it. The objective of this study is to evaluate the efficacy of an educative method in the routine of hand washing in the ICU before and after having contact with the patient The study was perfomed in a general ICU with eight beds and is composed of two parts. In the firs part an anonymous observer checked all the times an ICU professional had contact with the patients and washed or not his hands before and after this contact. This was repeated in the second part of the study after a doctor had oriented the professionals with lecture, written material and posters. At none part of the professionals were noticed about its existence. At the first part there were 515 contacts. Hand washing occurred in 25 (4,8 por cento) opportunities before and in 62 (12 por cento) after contact with the patients. In the second part there were 473 contacts with hand washing in 87 (18,5 por cento) times before and 141 (29,6 por cento) after having the contact. The aderence to hand washing was significantly better after orientation (p menor 0,0001) before and after the contacts but still is very unsatisfactory, showing the importance of frequently remembering the importance of this habit