The compressibility of krypton containing 0.90 mole percent xenon has been measured from 0° to 300°C and over the density range 1 to 10 mole per liter. The constants of the Beattie-Bridgeman equation of state for the sample and for pure krypton were determined. The constants for pure krypton are R=0.08206, A0=2.4230, a=0.02865, B0=0.05261, b=0, c=14.89×104 in units of standard atmos, liter per mole, and °K(T°K=t°C+273.13). The equation for the sample studied reproduced the observed pressures with an average deviation of 0.16 percent. The weight of one liter of Kr at a pressure of one standard atmosphere is calculated from the molecular weight (83.7) and the above constants to be 3.745̄ g per liter at 0°C and 3.474 g per liter at 70°F.