  In a recently published letter [S. W. Kim, T. Sagawa, S. DeLiberato, and M.
Ueda, PRL 106, 070401 (2011)] the influence of particle statistics on
extractable work in the Szilard engine was discussed. We point out that the
expressions given there suggest no work extraction is possible in the low
temperature limit if more than two particles are used and thus are not optimal.
We argue that the optimal extractable work is in general higher and in
particular non-decreasing in the number of particles.
