  We study the BPS spectrum of monopole operators in ABJM theory. First we work
out the complete spectrum of the chiral ring by using a semiclassical analysis
of the field theory compactified on a two sphere. By properly taking into
account the full quantization condition of monopole charges, we show that the
moduli space of ABJM theory with Chern-Simons level k, -k is a particular Z_k
cover of the symmetric product of C^4/Z_k. We also work out in detail the
spectrum of fluctuations around half-BPS monopole configurations and we find
candidate states for a dual BPS configuration to the giant torus solution found
by Nishioka and Takayanagi in the supergravity limit. We also discuss more
general BPS states.
