Buriti is a palm tree from the Amazon region. The pulp fruit is an excellent source of vegetable oil, which is rich in β-carotene and tocopherol. The aim of the present research was to study the physicochemical, colorimetric and microbiological storage stability of the probiotic fermented beverage of buriti juice (Mauritia flexuosa) with Lactobacillus casei during refrigerated storage. Five formulations of buriti pulp juices were studied by varying the concentration of pulp (15, 20 and 25%) and sucrose (11, 13 and 15%) and submitted to fermentation with Lactobacillus casei to obtain probiotic juice. The choice of the best formulation was made through the sensory analysis for the attributes of flavor, aroma, consistency and overall impression. The juice selected by the sensorial analysis was packed in polyethylene plastic cups and subjected to shelf life study for 28 days at 4 °C. The analyses were carried out after overnight storage of probiotic fermented beverage of buriti samples, and after 7, 14, 21 and 28 d of storage, when the analyses for pH, total acidity (%), soluble solids (°Brix), humidity; colorimetric parameters CieLAB L*, a* b* and determination of viable cells Lactobacillus casei and count cells of Molds and yeasts, total coliforms and thermotolerant were performed. The results of the sensory analysis show that all samples probiotic juices were accepted by the tasters, with 15% of pulp and 13% of sugar being highlighted. During refrigerated storage for 28 days the juice remained physicochemical and colorimetrically stable. The viable cell count of Lactobacillus casei in the juice presented higher values than the minimum of 106 CFU/mL stipulated by the Brazilian legislation to be considered a probiotic drink and there was no growth of molds and yeasts and total coliforms.