Background: Data on iron deficiency anemia (IDA) and cognitive function in Indian children aged 5-10 years is limited. Objective: To study the extent of IDA, its impact on cognition and evaluate the effect of iron supplementation on cognitive function in children with IDA. Methods: Children aged 5-10 years (n=193) were grouped into overt (group I n=71,,Ia-received iron supplements, Ib -without iron supplement), latent (group II, n=48, IIa-received iron supplements, IIb -without iron supplement)) anemia and non anemia (Group III, n=74) categories. Basic hematological investigations (HB, MCV, peripheral smear and total iron binding capacity) were done at baseline to categorize into groups. Cognitive function tests were performed at baseline and at the end of the study. Deworming with broad spectrum anthelmintic agent Albendazole(400mg stat) followed by iron supplements for 3 months was administered to Group Ia and IIa children.Results: Of 193 children, 119 (61.65%) had Iron deficiency, seventy (36.27%) had overt anemia and 49(25.397%) had latent form. Mean ± SD Haemoglobin at baseline was 11.80 ±1.71gm/dL, MCV 82.07± 4.69 femolitres, TIBC was 403.58 ± 58.77µ g/dL. Cognitive functions were significantly (p<0.005) higher in non anemic children. Iron supplements were administered for 3 months to 58 students. Treatment compliance was 96.0%.Hemoglobin >12gms/dL was seen in 80.83% (156/193) had < 12 gms/dL, after iron supplements; Mean ± SD Haemoglobin was 12.76±1.39gm/dL and that of visual recall, digit span and clerical task changed from 5.63±1.08, 4.03±1.0, and 7.16±1.4, respectively to 6.34 ±0.82, 4.35 ±0.78 And 7.98 ±1.19 respectively. Higher scores were seen in those with Haemoglobin> 12 gms/dL. Conclusion: Non anemic children perform better than those with anemia; performance of those with latent anemia is better than those with overt anemia. Iron supplementation helps in improved performance in these children.