This research was carried out to determine the best seeding rate of some winter bread wheat (Triticum aestivum L) and barley (Hordeum vulgare L.) varieties grown in Trakya Region of Turkey to get the highest yield. Experiments were established in split plots in Randomized Complete Block Design with three replications between 2003 and 2005 in rain fed conditions at the Trakya Agricultural Research Institute in Edirne. Main plot treatments were Pehlivan, Gelibolu, Tekirdağ, Selimiye, Flamura-85 bread wheat and Lüleburgaz with Bolayır barley varieties, and the sub plots were five different seeding rates 300, 400, 500, 600, and 700 seed/m². In this research beside seed yield, the other yield components plant height, spike number per square meter, spike length, seed number per spike, 1000 seed weight, and test weight were evaluated. According to the statistical analyses, the best seeding rate of some bread wheat varieties for Pehlivan 400 seed/m²(170-180 kg/ha) Gelibolu, Tekirdağ, Selimiye 500 seed/m²(200-210 kg/ha), Flamura-85’de 600 seed/m²(230-240 kg/ha), barley varieties Bolayır 500 seed/m²(190-200 kg/ha) and Burgaz 600 seed/m²(210-220 kg/ha) were determined.

Key words: Wheat (Triticum aestivum L), barley (Hordeum vulgare L.), seeding rate, seed yield.