Introduction :__ampersandsignnbsp;Previous studies have indicated that a S. mutans is the most common bacteria implicated in the causation of dental caries. It has also been documented that S. mutans can easily colonise tooth brushes. S. mutans count as high as 106 has been recovered few minutes after brushing and a count as high as 104 is being retained after 24 hours after storage. The retention and survival of S. mutans poses a threat of reinfection. Numerous studies has been done to evaluate the effectiveness of 12% chlorhexidine, 1% sodium hypochlorite and normal saline as toothbrush disinfectants and research personnel have shown that chlorhexidine and sodium hypochlorite are very effective in disinfection. None have established the effective time for complete disinfection. None have addressed the question if the disinfected toothbrushes can be used again. We have in this study tried to standardize a time frame for effective disinfection and the effective concentration using a highly affordable and easily available disinfectant and most importantly with the Indian mother in mind. The purpose of this present investigation is to study the 1) In vivo contamination by mutans streptococci (MS) of toothbrushes after use on 72 children (6- 12years old) visiting a single physician. 2) To evaluate .9% normal saline as a toothbrush disinfectant. 3) To standardize the time for effective disinfection . 4) To prove that .9% normal saline when used as a toothbrush disinfectant for the right time is much superior than .12% chlorhexidine and 1% sodium hypochlorite in many ways. Materials __ampersandsignamp; Methods: The in use toothbrushes(less than 3 months of use) of 72 children whose DMFT indexes are already in record were submitted for S. mutans count and they were provide with new toothbrushes. The new toothbrushes were to be put to use for a month and then submitted to the physician__ampersandsignlsquo;s office at the stipulated date within an hour after the routine morning brushing. They were immediately analyzed for S.mutans count after 15 minutes, 30 minutes, 1hour and 8 hours of being treated with .9%NS. There was no reduction in the CFU after 15min, 30 min and 1 hour but there was an absolute reduction in the cfu after 8 hour disinfection in .9% NS. All these brushes were returned to the children after a routine tap water rinse and were put to regular use in the night. The parents have not reported any problem with putting them to reuse after disinfection with .9%NS. Conclusion: These results have addressed the concept of cheap, effective and user friendly routine house based toothbrush disinfection between use.