  In this paper we consider the ${\cal N}=1$ supersymmetric mKdV hierarchy
composed of positive odd flows embedded within an affine $\hat sl(2,1)$
algebra. Its B\"acklund transformations are constructed in terms of a gauge
transformation preserving the zero curvature representation. The recursion
operator relating consecutive flows is derived and shown to relate their
B\"acklund transformations.
