The aim of our study is to investigate the protective effect of Spirulina fusiformis against streptozotocin-induced diabetes in Wistar albino rats. Rats were divided into five groups: group I was normal control, group II was diabetic control (50 mg/kg b.w. of streptozotocin, i.p.), group III was Spirulina fusiformis (400 mg/kg b.w., p.o.) treated diabetic rats; group IV was Glibenclamide (0. 6 mg/kg b.w., p.o.) treated diabetic rats and group V was treated with Spirulina fusiformis (400 mg/kg b.w., p.o.) alone. There was significant elevation in the levels of blood glucose, serum lipid profile and serum renal markers (total protein, urea, creatinine and uric acid) in the diabetic rats. Also, diabetic rats showed significantly (P < 0.05) reduced antioxidant status (reduced levels of superoxide dismutase, catalase, glutathione peroxidase, glutathione-S-transferase and reduced glutathione; increased levels of TBARS), impaired oral glucose tolerance and elevated HbA1C. Spirulina fusiformis was able to normalize the above mentioned parameters. Significant histopathological changes were found in the pancreas, liver and kidney sections of the diabetic control group while treatment with Spirulina fusiformis was able to minimize the extent of tissue damage. Current study shows that Spirulina fusiformis possesses significant antidiabetic and antihyperlipidemic effects in streptozotocin-induced diabetic rats by effectively reducing the rise in blood glucose levels and lipid profile.