The net radial momentum transfer to an inertially confined spherical plasma as a result of the slowing down of fusion product ions is calculated assuming a straight-line path for the charged particles. It is shown that such a momentum is outwardly directed and that the importance of this momentum transfer relative to the total momentum is measured roughly by the ratio of its value to that of the radial derivative of the pressure. When applied to the hot core of a magnetically insulated, inertially confined plasma, it is shown that this effect is negligible. In the case of a standard implosion-type inertial fusion, however, the outward momentum transfer from fusion alpha particles is considerable and cannot be ignored.