Considering the importance of hands in the chain of transmission of microorganisms, this observational research investigated the material infrastructure and compliance of hand hygiene in an intensive care unit in the south of Brazil in 2010. The data was collected by direct non-participant observation and through the use of self-administered questionnaires to be completed by the 39 participants, which was analyzed with the assistance of the chi2 Test, descriptive statistics and quantitative discourse analysis. Although health professionals overestimate compliance rates, recognize the practice as relevant to the prevention of infection and refer there are no impeding factors, of the 1,277 opportunities observed, compliance was 26% and significantly lower before patient contact and the use of aseptic procedures than after patient contact: infrastructure was shown to be deficient. The results indicate risk to patient safety, and thus, the planning of corrective actions to promote hand washing is relevant.