  The Szilard engine is the simplest possible engine, composed only of one or
more particles in a box. The box is then immersed in a heat bath and
partitioned into two parts by a wall. It is known that in the cold temperature
limit, one may extract more work out of elementary boson than out of elementary
fermions. In this paper, we consider the amount of work that can be extracted
out of a system of composite particles -- particles which are composed of two
interacting elementary fermions of different species. We demonstrate that the
amount of work extracted is closely tied to the amount of entanglement within
the composite particles
