Aim: To test the efficacy of a multiple micronutrient fortified salt in improving the micronutrient status and health of school children and its effect on cognition. Methods: A salt fortified with multiple micronutrients was developed containing chelated ferrous sulphate, microencapsulated vitamin A, B1, B2, B6, B12, folic acid, niacin, calcium pantothenate and iodine. The efficacy of the fortified salt was assessed in 7-11 year old school children in Chennai, India. In the experimental group (N=63), the food in the school kitchen was cooked with the fortified salt for a period of one year. The control group (N=66) consisted of day scholars who did not eat at the school. Hemoglobin, red blood cell count, hematocrit, serum vitamin A, urinary iodine and prevalence of angular stomatitis were measured at baseline and at the end of the study after one year. A battery of 7 memory tests (The personal information test, the Mann-Suiter Visual memory screen for objects, The digit span forward test, The digit span backward test, The delayed response test, The Benton Visual Retention Test and The Cattells retentivity test), one test for attention and concentration (Letter cancellation test) and one test for intelligence (Raven's coloured progressive matrices) were administered to all the children at baseline and endline. Results: There was a significant (p＜0.05) improvement in the experimental group in hemoglobin, red cell count, urinary iodine and serum vitamin A whereas in the control group there was a statistically significant decline (p＜0.05) in hemoglobin, hematocrit, red cell count and urinary iodine. Angular stomatitis was eliminated from baseline 30.4% in the experimental group whereas it increased from 3.25% to 25.5% in the control group. In 4 tests out of the 7 memory tests and in the letter cancellation test for attention, the mean increment in scores in the experimental group is significantly more (p＜0.05) than the control group. There was no significant improvement in overall intelligence as seen in the Ravens progressive matrices between the experimental and control groups. Conclusion: The study shows that the multiple micronutrient fortified salt is effective in improving multiple micronutrient status and cognition in children.