Aqueous cationomeric polyurethanes (ACPU) were synthesized by a multistep reaction process. The alipathic diisocyanate, e.g., hexamethylene diisocyanate (HDI), was reacted with polyol, e.g., polypropylene glycol (PPG400) to form a prepolymer and it was chain-extended by reacting it with N-methyldiethanolamine (N-MDEA). Quarternization was then carried out by using dimethyl sulfate (DMS), acetic acid (HAc), or hydrochloric acid (HCl). The resultant cationomers were self-emulsified with deionized water. The effect of different percentages of N-MDEA in the polymer backbone on the structure and properties of ACPU were studied. Viscosity, thermal properties, electrolytic stability, and pH stability of the cationomeric polyurethanes were also studied along with the adhesion strengths between flexible and rigid surfaces.