A new analytical method that allows the rapid assessment of fish freshness and quality is presented. The method is based on 1 H high-resolution magic angle spinning (HR-MAS) NMR spectroscopy and allows the rapid determination of two well-established indicators of fish freshness and quality: the K value and the trimethylamine nitrogen (TMA-N) content. The method is demonstrated on four different species of fish (sea bream, sea bass, trout, and red mullet) stored on ice at 0°C. The results obtained are in agreement with more cumbersome methods classically used to determine the K value and the TMA-N concentration. The main advantage of the 1 H HR-MAS NMR approach is to allow a direct measurement of these two parameters directly on unprocessed fish sample without using any preliminary extraction. The total analysis time, including sample preparation, is of the order of 40 min per sample.