This paper describes the spatial uniformity of grafted layers of poly(glycydyl methacrylate) on the fibers of polypropylene nonwoven fabrics, and how they depend on the UV pretreatment step, the adsorption of initiator (benzophenone) to the fiber surface, and the UV grafting step. UV light transmission inside the nonwoven fabrics was measured to determine the effect of light intensity variations during the pretreatment and grafting steps. The light intensity decay depends on the pore size of the fabric and the presence of solvents in the nonwoven fabric. The adsorption of benzophenone to the fiber surface is lower in regions of low light intensity, resulting in a spatial variation due to the UV pretreatment. The presence of solvents tends to reduce light intensity decay during the grafting step. The results of this paper indicate how to avoid spatial nonuniformities during grafting by controlling the reaction conditions.