Objectives: Halimeter which a portable sulfide monitors, and Oral Chroma which a portable gas chromatograph, are devices that are widely used in the diagnosis of halitosis. The purpose of this study is to determine the amount of volatile sulfur compounds of periodontal healthy volunteers, periodontitis, and individuals having orthodontic treatment by Halimeter and Oral Chroma and to perform comparisons between the groups in the levels of halitosis. Materials and Methods: Thirty patients with periodontitis, 30 patients receiving orthodontic treatment and 30 healthy subjects were included in the study. Volatile sulfur compounds value of a total of 90 patients was measured by Halimeter and Oral Chroma. Results: Oral halitosis measurements between the three groups did not differ significantly between Oral Chroma and Halimeter. Tongue coating index, plaque index, gingival index, and probing pocket depth with the value of Oral Chroma and Halimeter results of oral halitosis showed a linear correlation in periodontitis group. Tongue coating index, and plaque index with the value of Oral Chroma and Halimeter results of oral halitosis showed a linear correlation in healthy group. Tongue coating index with the value of Oral Chroma and Halimeter results of oral halitosis showed a linear correlation in orthodontic group. Conclusions: Yongue coating was found to be the most decisive factor in estimating the odor score by both devices.