This study provides first hand comparative account of growth and antioxidative defense system of the wild type, Cu2+ and temperature treated wild type and acclimated strains of Anabaena doliolum Bharadwaja against Cu2+ and high temperature. The acclimated strains showed perceptible growth at 250 μM Cu2+ and 47°C temperatures, respectively. In contrast to this the wild type strain on exposure to 50 μM Cu2+ and 47°C temperature depicted almost complete inhibition of growth. However, the peroxide content was significantly higher in the acclimated strains than the wild type. Superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and glutathione reductase (GR) showed maximum activity at high temperature followed by Cu2+ acclimated and minimum in the wild type strains. The ascorbate (ASC) and glutathione (GSH) contents were increased by 2.3 and 43.3, and 15.5 and 36.5-fold in Cu2+ and 47°C acclimated strains, respectively. However, when the wild type strain was subjected to Cu2+ and temperature all antioxidative enzymes except SOD showed inhibition of their activity. In case of wild type the GSH content was inhibited by 0.39-fold at 50 μM Cu2+ but the ASC content registered increase by 2 and 2.7-fold on subjecting to Cu2+ and temperature, respectively. Thus increased activity of enzymatic antioxidants as well as accumulation of ascorbate and glutathione in both the acclimated strains suggests that enzymatic and non-enzymatic antioxidants help in the acclimation of A. doliolum Bharadwaja against Cu2+ and high temperature. However, inhibition of antioxidative defense system of wild type under Cu2+ and heat stress appears to be the reason for its non survival. In view of the appreciable increase in the level of antioxidants as well as greater inhibition of specific growth rate in temperature than Cu2+ acclimated strains, temperature (47°C) is proposed to be is more deleterious to the organism than copper (250 μM).