Proton n.m.r. chemical shifts and coupling constants are reported for trimethylene sulfite and 10 alkyl derivatives in CCl4. Data are discussed in terms of possible chair and non-chair conformations and results are compared with those from dipole moment studies. The shift reagent Eu(dpm)3 is used to aid configurational assignments. Conclusions from n.m.r. and dipole moments are consistent and indicate that several of the sulfites exist to a considerable degree in non-chair conformations.