<p>An experiment was conducted during the period from June to November, 2004 with a view to study the effect of storage relative humidity (RH) on germination and vigour of soybean seed. Four different storage relative humidities (viz. 50%, 60%, 70% and 80%) and two soybean varieties (namely, soybean cv. G-2 and soybean cv. PB-1) were included as experimental treatment. Seed moisture content (SMC), germination and vigour tests of seed were done one month interval starting from 10 July up to 10 November while the initial test for SMC and germination was done on 10 June, 2004. The result showed that storage relative humidity, variety and their interaction significantly influenced the seed moisture content, germination percentage and vigour index. The moisture content of soybean seed during storage were found between 7.9-8.5, 9.6-9.8, 12.0-12.3 and 15.3-16.1% for 50, 60, 70 and 80% storage RH, respectively against their initial moisture content of 8.4-9.5% just before storage. The germination and vigour of all the varieties decreased with increasing storage RH. For each of the soybean variety, the highest germination percentage was obtained from 50% storage RH and no seed germination was occurred in any of the variety stored under 80% storage RH after two months of storage. More than 92% seed germination was maintained for all the varieties after 6 months of storage. The seed stored under 70% RH showed 83% germination in July that reduced to 74% in November, 2004.</p>