Growth of Botryococcus braunii (race W) and production of its constituents viz, hydrocarbon, carbohydrate, fatty acid, and carotenoids were influenced by different levels of salinity. Under salinity at 34 mM and 85 mM, 1.7-2.25-fold increase in the relative proportion of palmitic acid and two fold increase in oleic acid were observed. A twofold increase in carotenoid content was noticed at 85 mM salinity with lutein (75% of total carotenoid) as the major carotenoid followed by P-carotene. The increase in biomass yields and changes in other constituents indicated the influence of salinity and the organism's adaptability to the tested levels of salinity (17 mM to 85 mM). (c) 2006 Published by Elsevier Ltd.