Childhood cancers and sickle cell disease represent some of the most complex medical conditions of childhood, impacting development in all domains. The influence of these conditions on cognitive functioning and academic achievement has particular relevance for the school psychologist, who is poised to promote the positive adaptation of children with these chronic illnesses in the school setting. This article provides a review of the research related to cognitive aspects of pediatric cancer and sickle cell disease. Based on that literature, science-based practice recommendations of relevance to the school psychologist are offered.