Controlling the risks associated with the flammability of polymeric materials depends on their flammability tests, as well as the existence of reference materials which are important tools for ensuring the quality of measurement results. In this study, polypropylene (PP) was prepared and tested to be a certified reference material for horizontal burning rate test instrument (UL94) in accordance with ISO guides and standards. Differential scanning calorimetry (DSC) and Thermo gravimetric analysis (TGA) were used to characterize some of the thermal properties like melting point and decomposition temperature of PP. The certified value of the PP burning rate was assigned by analyzing the data obtained through bi-lateral laboratory comparison involving two competent laboratories. The results of the burning rate measurements for the participating laboratories were clearly consistent and harmonic. The certified value and expanded uncertainty were calculated using results of characterization, homogeneity study and stability assessment and were found 19.63 ± 1.2 mm/ min at approximate confidence level of 95 %.