Synbiotic was a combination of prebiotics and probiotics. One of the agricultural commodities that contains prebiotics was "Pisang Ambon". Pisang Ambon and inulin as prebiotics and Lactobacillus casei as a probiotics can produce synbiotic beverages. To obtain synbiotic beverages, it needs a drink formulation that utilizes Pisang Ambon and use inoculum L. casei as a stater and adding inulin to obtain preferred synbiotic beverages. The objective of this research was to discover the most preferred formulation synbiotic beverages from puree of Pisang Ambon. This research was divided into three steps, the first step was the optimization of the use puree of Pisang Ambon and skim milk in synbiotic beverages using organoleptic test, the second was the addition of inulin as a prebiotic optimization at the best formulations of synbiotic beverages that obtained in the first step through sensory test and organoleptic test by doing hedonic rating test, and the third step was the analysis of the quality of the best synbiotic beverages in the second stage using parameters of chemical and microbiological quality. The result showed that ratio for skim milk: banana puree were 1: 1 with 2% inulin addition was the most preferable synbiotic beverage. Synbiotic beverages contains moisture 84.46%, ash 0.75%, 2.79% protein, 0.2% fat, 11.8% carbohydrate, number of LAB 3.6 x 10(9) cfu/ml, Coliform below the threshold and negative contamination of Salmonella.