Functional Near Infrared Spectroscopy (fNIRS) is a brain imaging technique that is well-suited for use in young children, making it particularly useful for investigating the neural bases of the development of executive functions. In the present study, children (ages 4-10) underwent fNIRS while completing response inhibition and working memory tasks. While both tasks were associated with increases in oxyhemoglobin and decreases in deoxyhemoglobin, we found that strength of activation increased with age and with improvements in task performance. These findings support the relation between emerging executive functions and maturation of the prefrontal cortex.