This paper introduces instrumental photon activation analysis (IPAA) utilizing short-lived products of photonuclear reactions, mainly (γ, n) and (γ, p), initiated by bremsstrahlung from the MT-25 microtron. A rapid nondestructive IPAA method for geochemical major element analysis is introduced as a tool for the basic geochemical characterization of rocks. Procedures were developed and parameters such as beam energy and irradiation-decay-counting times optimized with a representative set of geochemical reference materials, and an optimized scheme was applied in analysis of various geological samples. A complete analytical scheme combined with long-time irradiation IPAA and the possibility of utilization of photoexcitation reactions (γ, γ′) are briefly outlined.