Capsular polysaccharide produced by Haemophilus influenzae b (Hib) is the main virulent agent and used as the antigen in the vaccine formulation. In this study, an improved process of polysaccharide purification was established based on tangential flow ultrafiltration using detergents (cocamidopropyl betaine and sodium deoxycholate), two selective ethanol precipitations steps, and extensive enzymatic hydrolysis as strategy. The relative purity (RP) related to protein and nucleic acids were 122 similar to 263 and 294 similar to 480, respectively, and compatible with the specifications established by the World Health Organization for Hib vaccine, RP a parts per thousand yenaEuro parts per thousand 100. These results make this process simple, cheaper, efficient, environmentally friendly, and prone to be scaled up.