We develop a theory of quasiparticle localization in superconductors in sit
uations without spin rotation invariance. We discuss the existence and prop
erties of superconducting phases with localized/delocalized quasiparticle e
xcitations in such systems in various dimensionalities. Implications for a
variety of experimental systems, and to the properties of random Ising mode
ls in two dimensions, are briefly discussed.