This study was carried out to determine the effect of different sowing dates and seeding rate on seed yield, oil and protein contents of seed in two rapeseed cultivars in the field of experiment and application of Aydin Adnan Menderes University Faculty of Agriculture during 2014/2015 and 2015/2016. The experiment was the split-split-plot design with 4 replications. The sowing dates, cultivars and seeding rates were arranged to main, sub and sub-sub plots, respectively. This experiment was conducted applying two sowing dates (early and late), two winter type cultivars (NK Petrol and NK Caravel) and five seeding rates (3, 5, 7, 9 and 11 kg ha -1). The early sowing date and 7.0 kg ha -1 seeding rate given the highest seed yield for both cultivars based on two-year results. The interaction between sowing dates and cultivars for crude oil rate was significant, and the highest crude oil rate was recorded in NK Petrol cultivar (43.34 -43.54%) at the first sowing date in both years. Non-significant protein content for all factors and interactions varied from 19.10% to 23.72%. Finally, it was recommended the earliest possible sowing with 7.0 kg ha -1 seeding rate for seed yield and quality in winter rapeseed growing. Moreover, it was recommended that NK Petrol for early sowing dates and NK Caravel for late sowing dates should be used as a cultivar.