It has been suggested that the total bacterial count in the oral cavity may affect the degree of oral cleanliness. However, there are few methods to rapidly and conveniently measure the total oral bacterial count. The present study proposes a simple and convenient oral cleanliness test, which clarified the relevance of the total bacterial count in the mouth rinse solution (MRS), using the ammonia concentration and or turbidity as an indicator. The subjects consisted of 287 employees (40.2 ± 9.6 years old) who underwent periodic medical and dental examinations The MRS was collected after rinsing with 3 mL of distilled water for 10 s, and then used as the sample solution The total bacterial count in the MRS was measured by the real-time PCR method, the ammonia concentration was measured using ammonia test paper (Ami-check Pocket-chem BA PA-4130), and the turbidity was measured by absorbance at 660 nm (OD660) employing a portable photo-elec. photometer (ANA-118A+). The concentration of ammonia and turbidity (OD660) of the MRS showed a relatively strong correlation with the total bacterial count (r = 0.774, 0.750, resp., p <0.01). These results suggest that the concentration of ammonia and turbidity (OD660) of the MRS are useful indicators of oral cleanliness. Addnl., these values and the total bacterial count of the MRS also increased with age. Furthermore, subjects with a high CPI 34 code (periodontal pocket depth of 4 mm or more) had a significantly higher concentration of ammonia and turbidity (OD660) than those with CPI 0-2. Based on these results, it is suggested that the concentration of ammonia and turbidity (OD660) of the MRS are useful indicators of oral cleanliness and the periodontal disease risk.