Zero echo time imaging (ZTE) of deuterium oxide (D2O)-exchanged unfixed white matter is a proven method for measurement of myelin density. In this work, we perform D2O-exchanged ZTE measurements on human spinal cord tissue before and after formalin fixation to assess whether fixation, which cross-links proteins, impacts the measured myelin density. A segment of human spinal cord was obtained at autopsy, subjected to D2O-exchanged ZTE myelin density measurement, chemically fixed using formalin, and re-measured. Signal intensity was 31.36%, normalized to a reference, before fixation, and 31.44% after fixation. These similar measurements support this method’s accuracy in fixed tissue.