İntensive care patients needs to oral assessment and oral care for avoid complications caused by orafarengeal bacteria. In this literature review, it is aimed to determine the practice over oral hygiene in mechanical ventilator patients in intensive care unit. For the purpose of collecting data, Medline/pub MED and EBSCO HOST databases were searched with the keywords „oral hygiene, oral hygiene practice, mouth care, mouth hygiene, intubated, mechanical ventilation, intensive care and critical care” between the years of 2000-2012. Inclusion criteria for the studies were being performed in adult intensive care unit patients on mechanical ventilation, published in peer-reviewed journals in English between the years of 2000-2012, included oral care practice and presence of a nurse among researchers. A total of 304 articles were identified. Six descriptive evaluation studies, three randomised controlled trials, four literatüre reviews, three meta-Analysis randomized clinical trials, one qualitative study and one semi-experimental study total 18 papers met all of the inclusion criteria. Oral care is emphasized as an infection control practice for the prevention of Ventilator-Associated Pneumonia (VAP). In conclusion, we mention that oral care is an important nursing practice to prevent VAP development in intensive care unit patients; however, there is no standard oral evaluation tool and no clarity on oral care practice frequency, appropriate solution and appropriate material. It can be recommended that the study projects on oral care in intensive care patients to have high proof level and be experimental, and longitudinal.