Present study was aimed to investigate the anti-obesity activity of Spirulina platensis in high fat induced rats. Spirulina platensis was administered at a dose of 1000mg/kg to fat induced Rats for 30 days and changes in body weight, lipid profile, total proteins, albumin was evaluated in HFD (High Fat Diet) induced rats and was compared with the normal rats. The results demonstrated that feeding with HFD had caused a significant increase in weight gain compared with the normal chow diet fed rats, which was significantly decreased by the co-administration of spirulina platensis in a dose dependent manner. The present study clearly showed that giving spirulina platensis is beneficial for the suppression of diet induced obesity. This study indicates that the decrease in body weight might be contributed by the increased use of glucose by the tissues. There was a marked alteration in the values of hematological parameters. At the same time, liver enzymes such as AST, ALT and ALP considered responsible for cell damage are reduced by the spirulina platensis