Proton spin lattice relaxation times (T1) are reported for the -NMe3, [CH2]n, and terminal methyl protons in sonicated samples of aqueous dispersions of lecithins; these three resonances have distinct T1 values at each temperature measured, so that spin-diffusion to the terminal methyl or the -NMe3 cannot be the dominant relaxation mechanism; the effect of the crystalline to lamellar liquid crystalline phase transition is discussed.