  In this short note we discuss discrete torsion in orientifolds. In
particular, we apply the physical understanding of discrete torsion worked out
several years ago, as group actions on B fields, to the case of orientifolds,
and recover some old results of Braun and Stefanski concerning group cohomology
and twisted equivariant K theory. We also derive new results including phase
factors for nonorientable worldsheets and analogues for C fields.
