Purpose: The aim of the study was to identify effects of oral care protocol on bacterial floras of the oral cavity and oral health status of intubated patients in an intensive care unit. Methods: The participants were 60 intubated patients who were recruited from an intensive care unit of a university hospital from Dec. 28, 2010 to Mar. 25, 2011. The participants were randomly assigned into 3 groups of 20 patients according to the application time of oral care (1-minute oral care, 2-minute oral care, and 3-minute oral care groups). The numbers of bacterial flora colonies in the oral cavity was assessed before and after the oral care. Oral health status was assessed using a Korean version of the Oral Assessment Guide developed by Elier et al. originally. Results: The numbers of bacterial flora colonies were less after oral care than those before the care, but there was no significant differences among the 3 groups after the care. Oral health status was better after the oral care than it was before the care, but there was also no significant differences among the 3 groups. Conclusion: If well-trained nurses perform oral care for 1 minute using a chlorhexidine swab on intubated patients, the numbers of bacterial flora colonies will be reduced and healthy oral status will be maintained.