This research was conducted at Laboratorio de Analise de Sementes of Escola Superior de Agricultura Luiz de Queiroz, University of Sao Paulo, for the purpose of determining which of the several materials used to seed packaging contributed most efficiently to the preservation of coloniao pasture grass seed. Seeds of two lots, with 9.7% e 12% of moisture, were stored in packages made of the following materials: cotton sacks, layered kraft paper (four layers), and polyethylene (bags 0.35 mm thick). The plastic bags were hot sealed. These packages, each with 1.5 kg of seeds, were stored for one year under three conditions: warehouse (without temperature and moisture control); city chamber (temperature of 25°C and moisture of 45%) and cold chamber (temperature of 10°C and moisture of 90%). Seed characteristics were tested: moisture level, seed germination, first counting, emergence, accelerated aging and electric conductivity, in a randomized experimental design with four replications. From the statistical analysis of data, the conclusions were the following: a) seeds stored in warehouse were better preserved when packed in layered kraft paper; b) seeds stored in a dry chamber were better preserved when packed in layered kraft paper and cotton bags; c) seeds stored in a cold chamber were better preserved when packed in polyethylene sacks. KEY-WORDS: Storage; coloniao grass; seed.