We present a fully integrated CMOS receiver for micro-magnetic resonance imaging together with a custom-made micro-gradient system. The receiver is designed for an operating frequency of 300 MHz. The chip consists of an on-chip detection coil and tuning capacitor as well as a low-noise amplifier and a quadrature downconversion mixer with corresponding low-frequency amplification stages. The design is realized in a 0.13 mu m CMOS technology, it occupies a chip area of 950 x 800 mu m(2) and it draws 50 mA from a supply voltage of 1.8 V. The achieved time-domain spin sensitivity is 5 x 10(14)spins/root Hz. Images of phantoms obtained in our custom-made gradient system with 8 mu m isotropic resolution are reported. (C) 2010 Elsevier Inc. All rights reserved.