Eggplant cultivars differ from one another in a number of properties, among others, earliness of fruiting and the length of fruiting period. A considerable problem regarding eggplant field cultivation in Poland is relatively high failure due to characteristics of our climate. Two-factorial field experiment established according to randomized split-plot method in three replications, aimed at the assessment of yielding of five eggplant cultivars: Avan F₁, Black Beauty, Classic F₁, Epic F₁ and Vernal F₁ (I factor). Plants were planted between 4^th– 7^th June, on the experiment years. Fruits were harvested in the stage of optimum harvesting maturity (every 7 days) and after exceeding this stage (every 10 days) (II factor). There was recorded significant diversity in eggplant yield in the years of the experiment, as well as in relation to its cultivar and the stage of fruit harvesting maturity. High temperature and sufficient amount of precipitation favored eggplant development in 2008, which was proved by yield (23.48 t ha^-1) higher than that in next years, average by 71.4% in the case of marketable yield and by 7.5 times higher for early yield (11.87 t ha^-1). Vernal F₁, Epic F₁ and Avan F₁ cultivars produced yield ranging from 23.79–18.89 t ha^-1, while Classic F₁ and Black Beauty featured yield lower by half. The marketable yield of elder fruits was higher than the one regarding fruits harvested in their optimum maturity stage. The results of chemical analysis proved that fruits in optimum maturity contained higher dry matter and reducing sugars in comparison to elder fruits. Yet no proof was found involving differences in biological value of the examined eggplant cultivars.

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