The pig slurry composting has been recommended as an alternative to reduce the volume and pollution potential of liquid pig manure.The pig slurry composting application can influence the physiological and sanitary quality of proso millet(Panicum miliaceum L.) seeds and their effects vary with environmental conditions. The objective was to evaluate the effect of pig slurry composting in physiological and sanitary quality of proso millet crop seeds produced under field conditions.The research was conducted in southern Brazil under a no-tillage system in a Rhodic Hapludox. A randomized block experimental design was used with four replications and five treatmentsconsisted of: a) control without fertilization; and doses of pig slurry compost: b) 4.0 Mg ha-1 c) 8.0 Mg ha-1; d) 12.0 Mg ha-1.The application of PSC doses positively affects the vigor of proso millet seeds expressed by accelerated aging, seedling emergence in the field and germination. The PSC doses provided greater weight of thousand seeds, the doses being 8 and 12 Mg ha-1 the greatest results. The PSC doses did not influence the electrical conductivity, first count, cold test in soil. Sanity of proso millet seed is not influenced by the PSC doses.