A pressure-volume-temperature data set has been obtained for natural chromium spinel, using synchrotron X-ray diffraction with a resistance heated diamond-anvil cell (RHDAC). The unit cell parameter of the chromium spinel was measured by energy dispersive X-ray diffraction up to pressures of 26.8 GPa and temperatures of 628 K. No phase change has been observed. The observed P-V-T data were fit to the high-temperature Birch-Murnaghan equation of state, with V-0 fixed at its experimental value, yields K-0 = 209 +/- 9 GPa, (partial derivative K/partial derivative T)(P) = -0.056 +/- 0.035 GPa K-1, and alpha(0) = 7 +/- 1 x 10(-5) K-1. The temperature derivative of the bulk modulus (partial derivative K/partial derivative T)p of chromium spinel is determined here for the first time. The obtained K-0 is slightly higher than the previous results of synthetic spinel.