The objectives of this study were to determine how seed reserves varied with depth in topsoil stockpiles and to evaluate the effect of length of time of storage on the number of viable seeds and number of species of seeds. Soil samples were taken from five topsoil piles representing zero to three years of storage on the Elkol-Sorenson mine near Kemmerer in southwestern Wyoming. Seeds were extracted using flotation/separation methods and were tested for viability using 2,3,5-triphenyl tetrazolium chloride solution. Data were analyzed using nonparametric statistical tests. Overall density of seeds in topsoil piles was low. No relationship was found between depth into the topsoil pile and the number of seeds or species. The number of seeds and species in the topsoil pile showed no decrease with increasing length of time of storage. The proportion of annual species in the seed reserve was not shown to increase with length of time of storage. Comparisons were made between the species composition of the seed reserve in the topsoil piles and the species composition of vegetation on sites selected to represent the sites of origin of the topsoil. Factors affecting the density, species composition and species richness of stored topsoil were suggested to be the plant community on the soil to be removed, depth of soil removed, and timing of topsoil removal.