  We discuss the extended BRST and anti-BRST symmetry (including shift
symmetry) in the Batalin-Vilkovisky (BV) formulation for the Chern-Simons (CS)
theories in $(2+1)$ spacetime dimensions. Further we develop the superspace
description of BV formulation for such theories. Interestingly, the extended
BRST invariant CS theories can be described in superspace in covariant manner
with the help of one more (Grassmann) coordinate. However, a superspace with
two Grassmann coordinates are required for a manifestly covariant formulation
of the extended BRST and extended anti-BRST invariant actions for these
theories.
