An optical diagnostic technique for measuring 3D temperature distributions in a flame, making use of new emission tomography reconstruction algorithms, is presented. The new approach aims to overcome the limitations of previous application, of emission tomography to flames, which did not consider radiation absorption inside the flame. mainly because reconstruction algorithms used did not allow for the inclusion of an absorption correction term, and this constituted a major limitation to the accuracy of the technique. In this paper an experimental set-up, together with dedicated tomographic reconstruction algorithms that include a flame radiation absorption model. is developed and tested in non-premixed laboratorial flames. The results indicate that it is possible to reconstruct the 3D-temperature fields of either axissymmetric or non-axissymmetric flames, with uncertainties below +/-10%, provided that soot is available.