The electronic stopping powers of ions of H, He, C, O2, and N for tissue were estimated on the basis of a method similar to the one used by Knipp and Teller, and the atomic (non-ionizing collisions) stopping powers were calculated on the basis of Bohr''s theory. The biological dose delivered by these ions is calculated using the variation of RBE with linear energy transfer as recommended by the National Committee on Radiation Protection (National Bureau of Standards Handbook 59).