Water-soluble polymer, cationic poly(N-[3-hexyldimethyl-aminopropyl]methacrylamide bromide) (PHDAPMAA), is synthesized by radical polymerization and studied in terms of its solubility, viscosity, surface tension and conductivity. Viscometry and surface tension measurements confirmed that intramolecular hydrophobic microdomains were formed by the pendent alkyl chains. Conductivity of cationic polymer in aqueous solution was determined. Variation of conductivity versus concentration in investigated system exhibits a typical polyelectrolyte behaviour.