The purpose of this study was to investigate the productivity of sunflower hybrids grown under conditions of organic farming as well as the efficiency of foliar feeding with organic fertilizer Biophalfa (Alga 300) at rate of 1 l.ha-1. The research was carried out on the certified field of the Field Crops Institute, Chirpan, Bulgaria, under non-irrigated conditions after durum wheat on soil type Pellic Vertisols. Seven sunflower hybrids were tested: Sanay, NK Meldimi, NK Alego, NK Ferti, DKF2120, P64LE10 and P64LE11. The results demonstrated that sunflower hybrids can be successfully grown under organic farming conditions. In favorable years can be realized a seed yield of 2.34 t.ha-1, and in drought - about 1.45 t.ha-1. Out of the tested sunflower hybrids, DKF2120 achieved higher seed yields without and with feeding - 1.83 and 1.96 t.ha-1, respectively. The average yield of dry biomass was 7.59 t.ha-1. Differences between hybrids were significant - from 6.91-6.95 t.ha-1 for P64LE10 and P64LE11 to 8.10-8.40 t.ha-1 for DKF2120 at both rates of feeding. The average harvest index for seed yield was 0.23, with a variation from 0.19 to 0.33. Hybrids P64LE10 and P64LE11 had a high harvest index. After fertilization, the harvest index showed an increase of 4.3%.