This research was aimed to evaluate the effect of drought stress, induced by polyethylene glycol (PEG6000), on physiological and biochemical parameters of black cumin (Nigella sativa L.). The traits were included: shoot dry weight, electrolyte leakage, relative water content, photosynthetic pigments (chlorophyll a, b, total chlorophyll and carotenoids), malondialdehyde and other aldehyde's contents, anthocyanines, polyphenol compounds, flavonoids, phenylalanine ammonialayse activity, soluble sugar content and protein. An experiment was conducted as a completely randomized design with three replications under hydroponic culture at research laboratory of Shahid Bahonar University of Kerman in 2011. Treatments were four levels of drought stress (0, -0.2, -0.4 and -0.6 MPa). Results showed that drought stress caused a significant reduction in shoot dry weight, relative water content, photosynthetic pigments, anthocyanines, polyphenol compounds, flavonoids and protein and an increase in electrolyte leakage, malondialdehyde content, phenylalanine ammonialayse activity and soluble sugar. Based on the obtained results, it seems that this plant is sensitive to drought stress, and the application of exogenous protective compounds could increase the antioxidant capacity of plant against stress condition.