This study examined the tongue coating index and halitosis to determine the association with the oral care behavior and variation in halitosis according to the tongue coating index, dental calculus, and the oral environment before and after scaling among 130 participants in scaling practices of the Department of Dental Hygiene at K University in Daejeon. The subjects were asked to participate in a survey, in an oral examination for the tongue coating index, dental plaque, and dental calculus status, and in halitosis measurement. The tongue coating most significantly affected halitosis and the tongue coating index was strongly correlated with smoking and tongue washing. More frequent toothbrushing, a lower level of halitosis; and nonsurgical treatment of scaling were effective in reducing halitosis; age was associated with the tongue coating index. Therefore, it will be necessary to perform good oral care and reduce the amount of dental plaque and tongue coating and undergo regular scaling with the objective of improving oral health and reducing halitosis.