The saturation of light‐induced defect density in hydrogenated amorphous silicon (a‐Si:H) has been studied as a function of various material parameters, such as initial defect densityNinit, Urbach energyEu, hydrogen contentcH, hydrogenated void fractionR, and deposition‐induced annealable defect density &Dgr;Nann. These parameters were varied by depositing samples at various substrate temperatures or by postgrowth anneals of samples grown at low substrate temperatures. It is found that total defect density of saturated light‐soaked stateNsatis well correlated with theNinit,Eu,cH,R, and &Dgr;Nannin the as‐grown states but no correlations betweenNsatand parameters other than theNinit,Eu, and &Dgr;Nannin the annealed states are found. It is also observed that annealing before light soaking reduces theNsatsubstantially. In particular, it is found that the value ofNsatfrom the fully annealed state is much lower than that from the as‐grown state with similarNinitandEu. A possible parameter that plays a primary role in the saturation of light‐induced defects is discussed.