The objective of this research was to determine the genetic gain in grain yield and grain quality accomplished by recently developed domestic soybean elite lines and to determine ways to improve these traits further. Realized gains were estimated by comparing recently developed most promising domestic soybean lines of maturity groups (MGs) 00, 0 and I with commercial cultivars (standards) in comparative field tests during three consecutive years (2002-2004) in Osijek, Croatia. Mean values, broad-sense heritability, genetic gain and relative genetic gain from selection were calculated for grain yield, protein and oil content in grain. The obtained results of biometrical analysis showed genetic improvement in productivity and quality of new domestic soybean elite lines within MGs00, 0 and I. The high agronomic performances of this breeding material will considerably contribute to the increasing and improving soybean production in our region as well as genetic improvement of domestic soybean cultivars further.