This study was done to evaluate the effect of fixed orthodontic patients on the level of oral streptococci, Streptococcus mutans, lactobacilli, yeasts in saliva. 35 patients wearing bands were compared with age-matched 35 non-banded control group by colony counting method on the specially designed culture medium. The following results were obtained; 1. The colony forming unit(CFU) of total streptocci per militer of saliva in subjects with or without orthodontic treatment showed no significant statistical difference between them(p>0.05). 2. The colony forming unit(CFU) of total Streptococcus mutans per mililiter of saliva in subjects with orthodontics treatment showed significantly higher than those without orthodontic treatment(p<0.05). 3. The colony forming unit(CFU) of total lactobacilli per mililiter of saliva in subjects with or without orthodontic treatment showed no significant statistical difference between them but higher tendency in those with orthodontic treatment(p=0.052). 4. The colony forming unit(CFU) of total yeasts per mililiter of saliva in subjects with or without orthodontic treatment showed no significant statistical difference between them(p>0.05).