Microwave-mediated desilication was successfully used to fabricate hierarchically structured zeolites combining micro- and mesoporosity. The application of microwave radiation during alkaline treatment of commercial ZSM-5 samples in aqueous NaOH solution at 338 K spectacularly accelerates the development of intracrystalline mesoporosity compared to the standard treatment (conventional heating). This is attributed to the more efficient transfer of thermal heating to the zeolite solution, thus enhancing the rate of silicon extraction. Very short exposure times (3-5 min) resulted in hierarchical zeolites with mesopore surface areas up to 230 m(2) g(-1) and pores centred around 10 nm, while preserving the crystallinity of the parent sample. The benefits of this treatment can be extrapolated to other zeolite structures.