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The influence of temperature on growth and biochemical constituents of two species of Spirulina; Spirulina platensis and Spirulina fusiformis was studied. Various temperatures as 20, 25, 30, 32, 35, 37 and 400C were investigated. Maximum specific growth rate of 0.141 was found at 320C for S. platensis and that of 0.144 was found at 370C for S. fusiformis. Both species showed negligible growth at 200C and 400C and after 6?8 days culture collapsed. Maximum protein content was found at 320C for S. platensis and at 300C for S. fusiformis and was 59.0 and 62.3 %, respectively. At 370C a significant increase in carbohydrates and in lipids were observed for both species; S. platensis (29.3 and 10.5%) and S. fusiformis (24.3 and 11.0%). Maximum biomass production of 2.4 g l-1 and chlorophyll a production of 16.6 mg l-1 were observed at 320C for S. platensis. Maximum biomass production of 2.3 g l-1 and chlorophyll a production of 14.2 mg l-1 were observed at 370C for S. fusiformis. A net increase in phycocyanin occurred in both species when cultures were grown at the suboptimal temperature of 250C. From the results the optimal growth temperature for S. platensis found at 320C and that for S. fusiformis found at 370C. It can be concluded from the findings that both species are suitable for culture in the tropics.