Two field experiments were conducted to study the effect of black cumin (Nigella sativa L.) seed oil and seed cake on cucumber productivity (Prince cv.) and associated microorganisms. Seed cake was applied as soil addition before transplanting at rates of 0, 5, and 10 g per plant, while seed oil in 0, 0.5, 1and 1.5% solutions was applied as foliar application three times every 10 days beginning within 30 days of transplanting. Plants receiving the highest levels of seed cake (10 g) and seed oil (1.5%) showed high density of total bacterial counts; Azotobacter chroococcum, Azospirillum brasilense and Bacillus megaterium, and high rates of CO₂ evolution. However, the same treatments gave the lowest density of total fungal counts, including some pathogenic fungi (Fusarium, Rhizopus and Aspergillus niger).  Both soil amendment and foliar application improved the growth characters of the cucumber, including the percentage of stand, the number of branches, plant height, the number of flowers and total chlorophyll as well as, the yield and fruit size.