THE AIM of this study is evaluating the effects of nutrients deprivation in growth media of Azolla caroliniana plant on growth and production of various phenolic components and antioxidant activity. Nutrient-deficient cultures (0.2, 0.1, 0.05 strength Hoagland solution) of Azolla plants resulted in a significant reduction in Azolla biomass, particularly with 0.05 strength compared to those grown on nutrient-sufficient culture (control). The doubling time (DT) and relative growth rate (RGR) were significantly affected with different Hoagland strength and that was accompanied with a significant accumulation of H2O2 and MDA. Anthocyanins, total flavonoids and total phenolics were enhanced in starved-Azolla. HPLC analysis of phenolic acids revealed a significant increase in caffeic, o-coumaric and t-cinnamic acids in Azolla grown on 0.2 strength Hoagland culture, whereas coumaric acid was markedly accumulated in Azolla plants grown on 0.1 strength media. There was a significant increase in phenylalanine ammonia lyase (PAL) and antioxidant activities in starved Azolla. The results indicated that, the antioxidant activity might depend mainly on phenolic compounds