The conditional Monte Carlo method of sampling has been applied to the spatial part of the gamma-ray transport problem in an infinite medium for the purpose of evaluating its general usefulness and its applicability to deep penetration problems. A simplified derivation of the application is presented, and the results of calculations for a water medium and a lead medium are shown. The calculations indicate that the conditional Monte Carlo method, as used in this application and without the aid of other special techniques, gives reasonably good results in a physical deep penetration problem out to approximately 10 mean free paths penetration distance independent of the absorbing properties of the material and can be carried out to 20 mean free paths if some inaccuracy can be tolerated.