Nata de coco rich in high dietary cellulose microfiber of low calories and thus suitable to be promoted as healthy drink is derived from bacterial fermentation of coconut water (an agricultural by-product). In this study the optimal amount of nata de coco to be added to mao juice was investigated. Nata de coco was produced by using Acetobacter xylinum TISTR 86 cultured at 30oC for 15 days in a plastic box containing culture medium which was composed of 92.5% coconut juice 0.5% ammonium sulfate 5.0% sucrose and 2.0% vinegar. Hedonic scale (1-9 point) sensory evaluation was used to select the optimal ratio of nata de coco from the 3 ratios of 5 10 and 15% to be added to mao juice. Based on taste and overall liking the most favorable mixture is to add nata de coco of 10% to mao juice. Finally the chemical physical and microorganism properties of mao juice with nata de coco in a 180 ml clear-glass bottle were measured after it was stored at room temperature for 1 month. This mixture product was found to beneficially contain fiber two times the amount of that of sole mao juice. The result suggests that these variable parameters of mixture product were accepted base on the Thai Community Product Standard (486/2547).