In the years 1995-1996, in a microplot experiment changes in the yielding and yield components and architecture of the stand of two oat cultivars (CHD 894, STH 2594) as influence by several seeding rates (400, 600, 800 grains per 1 m²) were investigated. Yields of oat cultivars were unaffected by sowing rate, because numbers of both spikelets and grains per panicle and weight of grains from the panicle were significantly reduced. The potential output of oat stands obtained from sowing density was decreased by increased percentage of 1-shoot plants and by larger percentage of shorter, less productive shoots.