From an eco–economic perspective, the efficient use of nitrogen is becoming incrementally worthwhile in crop management. Therefore, growth, yield and seed yield response index of three sesame varieties (Shandwel–1, Giza–32 and Sohag–1) as affected by four N rates (0, 72, 108 and 144 kg N ha−1) were investigated during two seasons of 2013 and 2014. The study illustrated that Sohag–1 was the superior variety for achieving SPAD value and seed yield ha−1. Sesame plants can be fertilized with N at a rate of 108 kg ha−1 being recorded higher seed yield ha−1. Integration between proper variety as a genetic factor with the appropriate N rate applied as an environmental one, i.e. Sohag–1 x 108 kg N ha−1 (or Sohag–1 x 144 kg N ha−1) considered a marked practice for gaining high sesame seed yield as an economic product. Being Sohag–1 exhibited less reduction in yield under low N rate and highly response with high N applied it belongs to ER group.