Addition of the hydrotropic salt sodium tosylate (TSNa) to solutions of a polymerizable cationic surfactant, methacryloyloxyundecyltrimethylammonium bromide (MUTB), leads to a transition from spherical to wormlike micelles about 40 nm in length. The wormlike micelles were successfully polymerized to yield stable, single-phase solutions of polymerized micelles. The polymerized wormlike micelles were several hundred nanometers long, although their cross-sectional radius remained unchanged (similar to 2 nm). The spherical to wormlike micelle transition, and the wormlike micelles polymerized at different molar ratios of TSNa to MUTB, were characterized using quasi-elastic and static light scattering, small-angle neutron scattering, NMR, and cryogenic transmission electron microscopy.