A Pulsed Nuclear Magnetic Resonance (NMR) method was used in this work to study water protons in skeletal muscle. The transverse relaxation times (T2) and total magnetisation of the water protons (h()) were examined as a function of temperature in the range +1.5 C to -54 C. The following results were obtained: (1) The dependence of both T2 and h() upon temperature exhibits hysteresis; (2) T2 decreases with decreasing temperature, with a characteristic activation energy of about 9.2 kcal per mole; and (3) The fraction of "non-frozen" water remaining in a sample below its nucleation temperature decreases with decreasing temperature from 19.4% at -1.2 C to 13.5% at -47 C.