NCH3, CH2-1, and omega-CH3 H-1 NMR signals of 2.5 x 10(-5) M dimethyl di-n-dodecylammonium chloride ( DDDACl) are sharp in D2O with expected line shapes, but the line width of NCH3 increases markedly to ca. 10 Hz and the omega-CH3 triplet is distorted at 10(-4) M, where electrolytic conductance had earlier demonstrated premicellar formation. The N-CH3 signal sharpens, and the resolved omega-CH3 triplet signal reappears at ca. 2.5 x 10(-4) M DDDACl where there was earlier evidence of micellization. All of the H-1 NMR signals become broad and ill-defined at > 10(-2) M DDDACl where there is growth and a structural change of the association colloid.