Measurements of the diffusion parameters of heavy water were made using a 1 Mev Van de Graaff accelerator utilizing the Be9(d, n) reaction under pulsed operation. The measurements were made at temperatures of 10°, 20°, 31°, 40°, and 50°C for buckling values ranging from 0.063 cm−2 to 0.100 cm−2. The decay of the neutron density was measured by a BF3 counter, located under the moderator container, in conjunction with a 26-channel time analyzer. The meanlife for each buckling was computed using Peierls' method; and values of the diffusion parameters were computed by the method of least squares. The value of the diffusion constant, (2.00 ± 0.04) × 105 cm2/sec at 10°C, agreed within the limits of experimental error with that found by Raievski and Horowitz, who used the modulated source method. The coefficient of the B4 term, usually referred to as the diffusion cooling coefficient, was found to be (3.72 ± 0.50) × 105 cm4/ sec as compared with (3.5 ± 0.8) × 105 cm4/sec as reported by Sjostrand in 1959.