Objective: The development of modern digital media, especially smartphones, has contributed to a fundamental change in the leisure activities and communication practices of adolescents. Besides the technical possibilities, the amount of multitasking, i.e., the parallel use of several media alone or in combination with nonmedia activities, has gained in importance. This article addresses the bidirectional relationships between multitasking and cognitive processes, consequences for performance, and the potentially negative effects on psychosocial health. Methods: This review article is based on a Medline research involving studies and reviews published on multitasking in digital media since 2000 concerning adolescents and adults. Results: Multitasking is involved in specific neuropsychological processes of the frontal cortex and, in part, the corpus striatum. Up to an individually defined level and an objectively defined performance capacity, multitasking does not necessarily haven a negative impact on the quality of work. However, if excessive individual or objective stress occurs, especially in very young children, respective reactions and negative consequences for psychosocial health occur. Conclusion: According to present research results, multitasking should not be exercised in tasks requiring complex cognitive conditions. Many further studies will be required to assess the relationship between multitasking and specific psychiatric diseases, especially addictive disorders and ADHD, but also its useful implementation in educational settings has to be explored.