Senegal initiated a program to improve the nutritional status of school-age children with the use of spirulina. The objective of this study was to evaluate the effects of spirulina on academic performance of school children in the municipality of Dakar, Senegal. The evaluation was conducted as a prospective study, comparing school performance of schoolchildren from public elementary schools located in three National Education Departments of Dakar (before supplements, during and after). The study population consisted of students from six schools randomly selected among the 100 who were in the program. We included all children with agreement of their parent or guardian, and those who rejected the spirulina were not included. Supplemental feeding with spirulina was given to young children during two months (from mid-April to mid June 2005). Over these 60 days, the students took a daily dose of 2 grams of spirulina mixed with 10g of honey to make the taste acceptable. The data on age, gender and monitoring of school performance (i.e. the average compositions of the second and third quarters) were collected. Mean differences in grades between second quarter and third quarter (after two months of supplementation) were analyzed and compared by the paired student test. The sample size was a total of 549 schoolchildren: 273 (49.72%) were girls, and 276 (50.28%) boys. The mean age was 91 months [90.29-91.71]. The average of 2rd quarter marks before supplementation was 5.17 out of 10 IC = [4.99-5.35] and the same for the 3rd quarter after two months of supplementation was 5.78 out of 10 IC = [5.59-5.97]. The mean difference between pupils' marks at the 3rd and the 2nd trimester was 0.59 (p <-- 0.0001). After two months of supplemental feeding, the academic performance of the children was improved.