2H-NMR is beginning to provide some insights into the way in which the hydrophobic surfactant proteins SP-B and SP-C interact with phospholipid bilayers in multilamellar structures. Both proteins have a significant effect on slow bilayer motions. In many ways, the effect of SP-C on the surrounding bilayer is similar to that of other transmembrane proteins. Ca2+ appears to modify the way in which SP-C perturbs the bilayers containing DPPG. The effect of SP-B on bilayers differs, in subtle ways, from that expected for a transmembrane protein.