A Monte Carlo code is employed to study the interaction of neutral beams with a field reversed configuration (FRC). The code follows the exact particle trajectories in the self-consistent equilibrium calculated including the beam and plasma currents. For high enough beam currents, a self-consistent confining effect is observed which prevents expansion of the beam along the FRC axis. The beam current drive and the power and momentum transferred are calculated for a variety of beam parameters. The results are slightly affected by the details of the injection geometry. The dependence on the neutral current IN and beam energy EN is influenced by several factors, such as particle losses through the ends, the density increase around the injection region and the finite Larmor radius effect.