Functional magnetic resonance imaging (fMRI) allows neuroscientists to examine the function of the human brain, especially the developing human brain, in a relatively noninvasive manner. The significance of studying functional brain changes in a developmental context becomes more apparent when aspects of brain development are considered. Several neuroimaging studies have examined developing sensorimotor systems in infants and young children. The prefrontal cortex supports representations of information against interference over time or from competing sources. A number of classic developmental studies have demonstrated that memory-related processes develop throughout childhood and adolescence. This chapter addresses the important themes of the development of age-appropriate behavioral paradigms and appropriate task designs in the context of four developmental fMRI studies. These empirical studies revolve around two central themes: maintenance of information in prefrontal cortex over time and suppression of competing responses in prefrontal cortex.