The condensation coefficient, a, for water near 0Β°C and 43Β°C was measured using the technique of vaporization into a closed system and was found to be 0042 and 0.027 respectively. The values of 01 for water obtained in the work are compared with previous measuremems at 15'C and 100Β°C. The data indicate an exponential denendence of 01 on temperature with an activation energv of -1520 cal/g mole. The experhnental rest.& give a temperature dependence for OT in agreememwith recent work reported on solids but not clearly indicated by calculations according to the free angle ratio theory. The condensation coefficient is discussed in terms of the rate of escape of liquid water moleculen, as estimated from the rate of rotation, compared to the rate of impingement of gaseous water molecules at the liquid surface. The values of OT calculated accordmg to this model are @035 at 0Β°C and 0034 at lOO"C, compared to the experimental values of 0.042 near 0Β°C and @02 at 100Β°C. The condensation coefficient for ice between -13Β°C and -2Β°C was found to be 0.0144, in contrast to values near unity measured below -40Β°C by others.