The broad line p.m.r. spectra of the alkali metal oleates have been observed from 77 °K up to or beyond the crystalline to waxy phase transition. Lower phase transition temperatures are observed in the oleates than in the stearates. This fact is attributed to larger entropies of transition in the oleates than in the stearates. The n.m.r. second moments indicate that in the stearates the packing of chains is probably not closer than in the oleates and consequently that the barriers to chain reorientation are not significantly higher in the stearates than in the oleates. Sodium oleate and stearate both appear to behave irregularly in the series of alkali metal soaps. Spin-lattice relaxation times have been measured by adiabatic rapid passage methods for both alkali metal oleates and stearates. Values ofT1and of the activation energy barrier for the reorientation of end methyl groups are compared with values obtained by other workers. No significant difference is seen between relaxation processes in stearates and oleates, at least in the lower temperature range. Soaps which seem to have some amorphous character have a second relaxation mechanism, in addition to end methyl group rotation, which is evidently important in the region of about 150–250 °K.