In Morocco, nutritional status or cognitive performance is rarely studied in school age children. Iron deficiency, the major cause of anemia worldwide, is associated with neuro-cognitive impairment in studies reported elsewhere. The aim of this work is to determine the levels of anemia and iron deficiency in Moroccan school children and to look for associations with cognitive performances. All pupils from an urban elementary school from grade one to four are recruited. After approval of the parents and administrative clearing, a medical team examined the children and venous blood samples were drawn. Ferritin level was determined by ELISA on the serum of the anemic children (HB < 11.5g/dl). A battery of objective tests were administered to the children (Extracts from WISC; Raven Progressive Matrix and the bells test) Anemia was observed in 23.4% of the pupils. Iron deficiency was the cause in 57% of children. Children did not perform well in Raven test but did better in WISC (Numbers recall) and the bells. The psychometric tests used showed that the temporary memory performance and the visual attention are higher than those of global intelligence in this sample and are higher in non iron deficient than in iron deficient children.