An embodiment of the invention relates to an integrated on-chip NMR or ESR device for performing chemical analysis and medical diagnostics. Specifically, the device contains, on a single substrate, a sample holding space, a magnet for generating a static magnetic field across the sample holding space and a microcoil for generating an excitation magnetic field across sample holding space. The magnetic fields are able to create NMR or ESR within a sample in the sample holding space and collect and/or process the signals from the NMR or ESR. The substrate may comprise an array of microcoils and sample holding spaces for performing multiple NMR or ESR analysis, such as multiple DNA analysis. Other embodiments of the invention relate methods for fabrication such devices and methods for performing NMR or ESR analysis using such devices.