Configuration interaction wavefunctions for the lowest eight terms of Si II have been computed using the non-relativistic Hamilitonian in the code CIV3. Energy levels are given together with the multiplet oscillator strengths of transitions between these terms. The oscillator strengths are compared with other recent work and are found to agree reasonably well with the theoretical results of Nussbaumer and Froese Fischer. They differ considerably, however, from some of the empirical values which Shull, Snow & York have derived by fitting interstellar absorption linewidths to curves of growth. A re-analysis of the measured equivalent widths shows that the theoretical oscillator strengths (excluding that for the 1808 Å line) give as good an over-all agreement with the observational data as those deduced empirically and we recommend adoption of the theoretical values.