We have developed an highly efficient electronic structure code, for parallel computers using message passing. The algorithm takes advantage of the natural parallelism in quantum chemistry problems to obtain very high performance even on a large number of processors. Most of the terms which scale cubically with respect to the number of atoms have been eliminated allowing the treatment of very large systems. It uses one of the most precise versions of Density Functional Theory, namely Self-Interaction Corrected Density Functional Theory. On a 6 processor Silicon Graphics Symmetric Multiprocessor based on the MIPs R8000 microprocessor, we obtain a performance of 6.3 Gflops per million dollar.