Gastric resident electronics, devices, systems, and related methods are generally provided. Some embodiments comprise administering (e.g., orally) an (electronic) resident structure to a subject (e.g., a patient) such that the (electronic) resident structure is retained at a location internal to the subject for a particular amount of time (e.g., at least about 24 hours) before exiting said location internal to the subject. In some embodiments, the resident structure is a gastric resident electronic. That is to say, in some embodiments, the resident structure is configured for relatively long gastric residence and comprises an electronic component. In some embodiments, the structures and components described herein may comprise one or more components configured for the delivery of an active substance(s) (e.g., a pharmaceutical agent) to the subject. In some embodiments, the device has a modular design, combining an electronic component(s) with materials configured for controlled and/or tunable degradation/dissolution to determine the time at which (gastric) residence is lost and the device exits the location internal to the subject. For example, in some embodiments, the resident structure comprises an electronic component and one or more additional components associated with the electronic component such that the resident structure is configured to be retained at a location internal to a subject for greater than or equal to 24 hours.