Background: Comprehensive oral care is an evidence-based, cost effective, essential routine nursing intervention that nurses ought to provide with good knowledge/understanding as it prevents and controls nosocomial infections especially Ventilator Associated Pneumonia (VAP) that is associated with increased morbidity and mortality in critically ill patients in Intensive Care Units (ICU). Aim of study: To determine ICU nurses’ knowledge, describe their practices and identify their perceptions regarding comprehensive oral health care to critically ill patients in order to refine or develop evidence based oral care protocol. Methods: A quantitative approach with a descriptive, exploratory survey was used for this study. A non probability convenience sample of thirty-four (34) ICU nurses from two public referral hospitals participated in this study. A questionnaire with a combination of open and closed ended questions was used to collect data on comprehensive oral care to critically ill patients. Results Thirty-four nurses responded to the questionnaire (response rate 89%). Only 18% (n=6) were knowledgeable about important aspects of oral care, while the majority, 82% (n=28) lacked knowledge on important aspects of oral care. Fifty-nine percent (59%) n=20 had received training on comprehensive oral care at basic nursing training and 44% (n=15) had orientation at unit level. Ninety-seven percent (97%) n=33 of the participants requested further updates on comprehensive oral care. No significant relationships were found between nurses’ demographic characteristics and knowledge of comprehensive oral care. All (100%) n=34 of nurses gave oral care a high priority and 91% ranked it very important for critically ill patients. Toothbrushes and toothpaste were used by 85% (n=29) of nurses and only 50% (n=17) used mouthwashes. The reason for non- use of mouthwashes was lack of supplies and not having been foreseen in unit protocol although neither of the units had an oral care protocol in place. / Thesis (M.N.)-University of KwaZulu-Natal, Durban, 2011.