A satisfactory diet is necessary for normal brain progress. Healthily nutrition is important especially at critical growth stages. Throughout childhood, under-nutrition causes children to have poor energy, which has adverse effects on cognitive development and academic performance. Under-nutrition also affects physical growth and maturation, therefore affecting growth rate, body weight, and final height. The present study is aimed to assess the nutritional status and cognitive performances in some school- age children (72-119 months).The present study is done on 51 students 25 boys and 26 girls with a mean age of 95.75±1.77 months. All students from cities Giza government. The mean average body weight, body height, BMI, and MUA were 23.65± 0.44 kg, 122.79±0.9 cm, 15.62±0.14kg/m², and 18.63±0.33cm respectively.  The mean average intake of total energy, protein, fat, and carbohydrate was 1185.02±29.12 kcal, 39.19±0.99 g, 39.40±1.27g, and 141.88±3.47 g respectively. The mean average intake of some minerals (Iodine, Iron, Selenium, and Zinc) was 83.08±5.47µg, 10.45±0.56 mg, and 49.32±2.05µg and 4.75±0.19 mg respectively. The mean average intake of some vitamins (Vitamin A, Vitamin B1, Vitamin B2, and Vitamin C) was 293.83±23.24 R.E, 0.41±0.04 mg, 0.47±0.03 mg, and 16.51±0.97mg respectively. Some biochemical analyses were done, the mean average urinary iodine was 155.29±3.53µg/l, and blood hemoglobin was 11.49±0.07 g/dl. The Wechsler tests were done to calculate student intelligence quotient (IQ), the mean average of verbal IQ was 98.43±0.99, the mean average of performance IQ was 95.09±0.42, and the mean average of total IQ was 96.69±0.42.From these results, it could be concluded that nutritional status may affect cognitive development, and the interventions and dietary supplements may improve cognitive abilities in children.