<sec> <title>Objectives</title> <p>The aim of this research was to determine intra-oral factors that affect halitosis in young women.</p></sec> <sec> <title>Methods</title> <p>This study was performed between March 2014 to May 2014, and included 35 women in their 20s with good oral health. Correlation and logistic regression analyses were performed to investigate the change in halitosis immediately, and 1 hour after scaling.</p></sec> <sec> <title>Results</title> <p>In both oral gas (OG) and extraoral gas (EG) groups, halitosis was reduced after scaling compared to before scaling. The logistic regression analysis of oral state factors in OG showed that as oral fluid [odds ratio (OR) = 0.792, <italic>p</italic> = 0.045] and dental plaque (OR = 0.940, <italic>p</italic> = 0.016) decreased by 1 unit, the OR in the OG group decreased (> 50). In addition, as glucose levels in the oral cavity (OR = 1.245, <italic>p</italic> = 0.075) and tongue coating index (OR = 2.912, <italic>p</italic> = 0.064) increased by 1 unit, the OR in the OG group increased (> 50). Furthermore, in the EG group, as oral fluid (OR = 0.66, <italic>p</italic> = 0.01) and dental plaque (OR = 0.95, <italic>p</italic> = 0.04) decreased, the OR in the EG group decreased (> 50) significantly.</p></sec> <sec> <title>Conclusion</title> <p>To control halitosis, it is necessary to increase oral fluid and decrease the amount of tongue plaque. Furthermore, maintaining a healthy oral environment, aided by regular scaling and removal of dental plaque, may significantly control halitosis.</p></sec>