Double-cropping of sesame (Sesamum indicum L.) with small grains has been quite successful across the southeastern Turkey. However, producers in this region use planting dates ranging from early May as main crop (normal) through late June as second crop (late). We investigated the effect of the two sowing periods (early May and late June) on oil and protein content and seed yield of sesame genotypes under agro-climatic conditions of southern of Turkey in 2003 and 2004 growing seasons. Results indicated that sowing time significantly affected seed yield, 1000-seed weight, oil yield and protein yield. The highest seed yield was obtained when sesame genotypes were planted late (20 June) as second cropping. Genotype Y-A30 produced the highest seed yield (1352.2 kg ha -1 ) across the 2-year study, averaging 430 and 422 kg ha -1more seed yield than Vara Verde and Muganlıvarieties, respectively. Results from the seed analyses indicated that no difference in oil and protein contents between sowing time was observed, while genotypes displayed significant variation amongst them for oil and protein contents. Furthermore, oil and protein yields appeared to change with sowing time and in general, the earlier sowing time decreased oil and protein yield as a result of higher pod yield.