Diabetes mellitus, a metabolic disorder of the endocrine system is found in all parts of the world and is rapidly increasing. People suffering from diabetes cannot produce or properly use insulin, so they have high blood glucose. Currently available antidiabetic agents have a number of serious side effects. Therefore, the search for more effective and safer hypoglycemic agents has continued to be an important area of investigation. There is growing interest throughout the world in Spirulina as a potential source of nutraceutical compounds, which have applications in health foods, feeds, therapeutics and diagnostics. In the present study, insulin is being screened in 23 Spirulina (Arthrospira) strains. The highest concentration (33.9 μg g −1 ) of insulin was found in Spirulina platensis CFTRI, Mysore. Its presence was further confirmed by SDS-PAGE, Western blotting and HPLC using bovine insulin as a marker. Culture condition manipulation for nitrogen, phosphorus, carbon and sulphate sources enhanced the insulin content in the test organism.