The thermo-physical properties are useful in designing manufacture processes for polymers, as they supply relevant information about the performance of the material during the different manufacturing stages. The thermal diffusivity is one of the most important of these properties because it contains information about other properties such as the heat capacity, the density and the thermal conductivity. Therefore, the analysis of the thermal diffusivity is paramount, especially when fillers are added to the polymer mixture, an example of those are the pigmentation masterbatches. Moreover, several methods and techniques have been developed to characterize the thermal diffusivity, such as the xenon-laser method. Using this method, the aim of this research is to determine the effects in the thermal diffusivity of a high density polyethylene after supplementing it with different kind of pigmentation masterbatches at a variable concentration (red, blue and gray). The results of the experimentation show the dependence of the diffusivity with temperature changes, which are affected by alterations in the composition and concentration of the added low density polyethylene (matrix of the masterbatch) and the inorganic material (pigment). These alterations are more evident in a domain of high temperatures, near to the melting temperature, in which case the competence between amorphous and crystalline phases is taking place [1]. The experimental data was compared with the results from a theoretical model found in the literature that predicts the behavior of the thermal diffusivity in a compound polymer [2]. These results are relevant in the manufacture process in polymers because it can explain the difference in the processing times by adding different kind of pigments, that are influenced by the concentration of the masterbatch instead the nature of the inorganic components.