Mobile electronic media is ever-present in the lives of young children and an examination of the behavioral byproducts following the use of these modalities is timely. The present study assessed the extent to which mobile electronic and print media interact with operant demand and delay of gratification in preschool children. Participants were six boys (Mage = 3.82 years, SD = 0.24) recruited from a university-run preschool. In Phase 1, participants allocated responses to buttons providing access to either a print book at a fixed-price (FR-1) or an e-book containing identical stimuli available at increasing prices (FR5--FR200) to examine substitution-like effects. In Phase 2, across 9--15 sessions, participants received access to either the print book, the e-book, or a fast-paced interactive tablet game, 3--5 times each in a randomized sequence; each engagement was immediately followed by a delay of gratification task (i.e., the Marshmallow Test ). In this task, participants could consume a single piece of preferred edible at any point or wait 5--10 min to receive two pieces. Delay of gratification was longest for all participants following access to print media. We discuss lower wait times following mobile electronic media conditions within the conceptual frameworks of escape from rich-to-lean transitions, reinforcer pathologies, and behavioral momentum.