We investigate the utility of cosmological and astrophysical observations for distinguishing between supersymmetric theories. In particular we consider 276 pairs of models that give rise to nearly identical patterns of observables at hadron colliders. We focus attention on neutralino scattering experiments (direct detection of relic neutralinos) and observations of gamma-rays from relic neutralino annihilation (indirect detection experiments). Both classes of experiments planned for the near future will make measurements with exceptional precision. In principle, therefore, they will have the ability to be surprisingly effective at discriminating between candidate theories. However, the ability to distinguish between models will be highly dependent on future theoretical progress on such things as determination of the local halo density model and uncertainty in nuclear matrix elements associated with neutralino recoil events. If one imagines perfect knowledge of these theoretical inputs, then with extremely conservative physics assumptions and background estimates we find 101 of the 276 degenerate pairs can be distinguished. Using slightly more optimistic assumptions about background rates increases this number to 186 of the 276 pairs. We discuss the sensitivity of these results to additional assumptions made about nuclear matrix elements, the cosmological density of neutralinos and the galactic halo profile. We also comment on the complementarity of this study to recent work investigating these same pairs at a (s)^1/2 = 500 GeV linear collider.