We propose two alternative formulations for a three-dimensional
non-anticommutative superspace in which some of the fermionic coordinates obey
Clifford anticommutation relations. For this superspace, we construct the
supersymmetry generators satisfying standard anticommutation relations and the
corresponding supercovariant derivatives. We formulate a scalar superfield
theory in such a superspace and calculate its propagator. We also suggest a
prescription for the introduction of interactions in such theories.Comment: 9 pages, revtex4, v3: some clarifications and references added,
version accepted for publication in Phys.Rev.