MW fractions of poly(dimethyldiallylammonium chloride) (PDMDAAC) were prepared by preparative size-exclusion chromatography and characterized by static and dynamic light scattering, viscometry, size-exclusion chromatography, and electrophoretic light scattering, in 0.50M NaCl solution. The behavior of fractions with MW < 2 X 10(5) was as expected for a strong polyelectrolyte in a good solvent, with a Mark-Houwink exponent of ca. 0.8, and MW-dependencies of the hydrodynamic radius and the radius of gyration of corresponding magnitude. At higher MW, curvature appears in the MW-dependencies, which can be best explained by the presence of branching. While this notably lowers the intrinsic viscosity at high MW, the electrophoretic mobility is unchanged regardless of molar mass. Thus, the branched polymers display the electroporetic free-draining behavior characteristic of linear polyelectrolytes.