Aggregation numbers (N-agg) and critical micelle concentrations (cmc) are reported for distearyldimethylammonium (DSDMA) hydroxide and chloride in aqueous solutions with and without added salt. The DSDMA hydroxide has a higher N-agg and cmc than either the chloride, bromide, or methyl sulfate DSDMA salts. The measured cmc’s were 1.5 x 10(-4) M for DSDMA OH and 3.0 x 10(-7) M for DSDMA Cl. The aggregation number for the DSDMA Cl is 63 (0.05 M NaCl) vs 6000 for the hydroxide at the same NaOH concentration. The DSDMA OH is highly soluble in water, forming spherical vesicles of size R(H) = 300 Angstrom, and does not flocculate upon addition of salt. The DSDMA OH vesicles revert to micelles with increasing surfactant concentration having an aggregation number of approximately 60. The same aggregation number for the hydroxide can be obtained by raising the salt concentration to 1.0-2.0 M NaOH, keeping the surfactant concentration constant. In the overlapping range with respect to DSDMA OH concentrations and salt, the appropriate hydrodynamic description is that of thread-like micelles, as determined from inelastic light scattering experiments.