The effect of seed size of cabbage seeds (Brassica oleracea L. Capikita group cv. Oscar) on germination, emergence, seedling growth and the sensitivity to rapid ageing were studied. Seed lots of 1984-1 and 1984-2 showing high vigour were separated into 3 fractions, unsorted seeds served as control. Seed size had no effect on germination and percentage normal seedlings in the standard laboratory germination test. It did also not affect the final percentage emergence at temperatures ranging 9 from 25℃ at phytotron conditions, nor the rate of emergence. However, seedling fresh-weight was closely related to seed size, the larger the seed, the better seedling growth. Thus, seed size influenced seedling growth irrespective of the physiological age of the seeds.