In view of the adoption of the International Temperature Scale of 1990 (ITS-90) which defines the International Celsius Temperatures t90, the dependence on temperature of the speed of sound in seawater is reexamined. The coefficients for two seawater sound-speed equations published previously, one by UNESCO (1983) which is also known as the Chen and Millero equation fo 1977, and one by DelGrosso (1974) are revised for application with the new temperature scale ITS-90. It is found that the resulting change in seawater sound speed is within 0.024 and 0.017m/s for the UNESCO and the DelGrosso equations, respectively, These changes are comparable to the numerical correction values suggested by Dushaw et al. (1993)