The temperature dependencies of the single crystal elastic constants and the isotropic elastic moduli of zircon were reevaluated using the ultrasonic in-phase frequencies vs. temperature data and the thermal expansion coefficients. The bulk moduli of zircon at different temperatures were also calculated using the recently derived analytical expression by Garai and Laugier (J. Appl. Phys. 101, 023514 (2007)) utilizing the Anderson-Gruneisen parameter (8) obtained from the pressure dependencies of the single crystal elastic constants. The temperature derivatives of the bulk modulus of zircon evaluated from the temperature derivatives of the single crystal elastic constants agree well with the corresponding values calculated from the analytical expressions utilizing the pressure derivative of the bulk modulus (8). The results reveal good correlations between the ultrasonic measurements of the pressure and temperature derivatives of the single crystal elastic constants of zircon. (c) 2008 Elsevier Ltd. All rights reserved.