Abstract Inorganic and organically-bound forms of selenium (Se) may be differentiated by monitoring the accumulation and distribution of Se in egg yolk and white of supplemented laying hens. In this experiment, the utilization of Se from a commercial selenized yeast product was compared to that of inorganic and organically-bound sources. Initially, laying hens were fed a low Se diet and then were continued on the basal diet for 4 weeks or were repleted with 0.3 or 5.0 ppm Se as sodium selenite, selenomethionine, or selenized yeast. Both the level and chemical form of dietary Se affected tissue Se concentration. Animals fed 5.0 ppm Se deposited significantly more Se in egg than hens fed 0.3 ppm Se, regardless of source. At both 5.0 and 0.3 ppm, Se from selenomethionine and selenized yeast was concentrated more effectively in egg yolk and white than the Se of sodium selenite. Based on levels of selenium accumulation and differential partitioning of Se between egg yolk and white, utilization of Se from selenized yeast more closely resembled that of selenomethionine rather than that of selenite. This bioassay may be useful for rapid preliminary speciation of Se from various dietary sources.