  We calculate the superconformal index for N=6 Chern-Simons-matter theory with
gauge group U(N) X U(N) at arbitrary allowed value of the Chern-Simons level k.
The calculation is based on localization of the path integral for the index.
Our index counts supersymmetric gauge invariant operators containing inclusions
of magnetic monopole operators, where latter operators create magnetic fluxes
on 2-sphere. Through analytic and numerical calculations in various sectors, we
show that our result perfectly agrees with the index over supersymmetric
gravitons in AdS_4 X S^7/Z_k in the large N limit. Monopole operators in
nontrivial representations of U(N) X U(N) play important roles. We also comment
on possible applications of our methods to other superconformal Chern-Simons
theories.
