Intraspecific hybridization is one of the most effective methods of creating valuable source material in breeding of spring vetch. The study of the nature of the variability of main agronomic traits of productivity of spring vetch hybrids makes it possible to assess the extent of their inheritance. Therefore, the main objective of our research was to study the effect of heterosis, the degree of dominance, coefficients of inheritance of main agronomic traits of productivity of spring vetch in conditions of the right-bank Forest-steppe Zone of Ukraine. The F1 hybrids from 20 combinations are obtained in 2011. The evaluation of hybrids populations F1 and parental forms is performed by the main elements of productivity of plant, including height, number of branches, number of productive units, number of pods, number of seeds per plant, weight of seeds per plant. From the result of hybridological analysis of F1 hybrids of spring vetch depending on the combinations of crossing the different character of inheritance – from the positive overdominance to depression are appeared. The hybrid populations with the highest rates of positive overdominance and the extent of true heterosis for all main traits of productivity: Pributhka 19/Irina, Sputnytsya/Pributhka 19, Sputnytsya/Irina are identified. The maximum expression of heterosis for main trait of seed productivity – weight of seeds per plant with a coefficient of true heterosis from 20.69 to 56.4 in hybrid populations Sputnytsya/Pributhka 19, Bilotserkivska96/Pributhka 19, Liliana/Irina and Pributhka 19/Irina is installed.