The capture of electrons by slow singly charged helium ions passing through helium gas is discussed theoretically. Calculations of the capture cross section for incident ion energies from 200 ev. to 100 kev. are made using an impact parameter method due to Kohn. In this energy interval the computed cross section is found to be fitted very closely by the empirical expression (σ/πa02) = 7.94 – 2.35 log10E(kev.). The results are compared with recent experimental data. The agreement between theory and experiment is good, except for the data of Keene.