Plasma heating and ignition by neutral injection have been studied using a Monte Carlo neutral injection computer code coupled to a single fluid, one-dimensional (1-D) transport code and a two-dimensional (2-D) flux conserving equilibrium code. It is shown that, by taking advantage of central ..cap alpha.. heating, profile effects, and flux surface shifts in elongated plasmas, it is possible to ignite a modeled, prototypical reactor plasma using 45 to 30 MW of 100 to 150 keV (D/sup +/) neutral beams. To do this, the plasma is started at full bore but low density. The density is then increased by peripheral fueling so that the central core begins to ignite before the time when the neutral beams no longer penetrate to this region. The fusion ..cap alpha.. particles take over the heating requirements in the core region. Because of the decreasing beam line efficiency with increasing energy, it is found that a nearly constant extracted power of about 85 to 95 MW is needed for ignition in the range studied. There is thus little economic difference in this energy range. However, higher energy beams around 150 keV imply fewer injectors and perhaps lower impurity production rates during heating to ignition.