A study of the effects of multibanded orthodontic appliances on the oral lactobacilli was conducted on 41 multibanded group and 41 caries free group. The following conclusions were obtained. 1. In multibanded group, the average count of lactobacilli per milli-liter of saliva showed about 219,300 in male and 254,100 in female. In caries free group, the mean count of lactobacilli per milli-liter of saliva showed about 66,700 in male and 68,500 in female, Therefore, the average of lactobacilli in multibanded group was much higher than that of the caries free group in both sexes. 2. The average of all the types of lactobacilli colonies (Disk-type, Bell-type, Y-type) in multibanded group was much more than that of caries free group. 3. Multibanded orthodontic appliances were found to sufficiently alter oral environment to significantly affect disk-types and total counts in both sexes and bell-type in female, at 1% level of confidence. But changes in bell-type and y-type, in male, were considered to be significant at 5% level of confidence.