Onions are one of the oldest vegetables in continuous cultivation dating back to at least 4000 BC. Onion seeds are difficult to store for longer periods as they may loose viability and vigour very quickly. Studies were initiated to explore the vigour, viability and seed membrane integrity at high temperature 45oC and high relative humidity in relation to seed germinability, time to get 50% germination and solute leakage in onion (Allium cepa L.) seeds.