Measurements of the first-order Raman spectrum in homoepitaxially grown synthetic diamond for the temperature range of 300 to 1200 K are presented. Similar measurements for natural type IIa diamond for the temperature range of 300 to 2000 K are also given. Both the Stokes and anti-Stokes components are analyzed for their intensity, Raman shift, and width variation with temperature. The depolarization of the Raman signal at elevated temperatures was found to be the same as that at room-temperature. The synthetic diamond Raman shift indicated the presence of internal stress. The experimental first-order Raman shifts for natural diamond, using units of cm-1 and absolute temperature, are conveniently expressed as (Delta)(nu) = a1T2 + a2T + a3 with the coefficients found to be -1.124 X 10-5 cm-1 K-2, -6.71 X 10-3 cm-1 K-1, and 1334.5 cm-1, respectively.