Abstract: This paper reported an investigation on the synergistic effects of talc and nano-organic montmorillonite (OMMT) on the polypropylene (PP) compounds flame-retarded with decabromodiphenyl ethane (DBDPE). Moreover, the effects of talc, DBDPE and OMMT loadings on the limited oxygen index (LOI), vertical combustion performance, mechanical properties and combustion behavior of the PP compounds were studied extensively. The results indicated that there was a significant synergetic effect of talc and OMMT on the flame retardancy of PP with DBDPE. The PP compounds exhibited an improvement in flame retardant standard for vertical combustion and a decrease in LOI with an increase of the amounts of talc and DBDPE flame retardant, and there was a further improvement with the addition of OMMT. The heat release rate, total heat release, smoke production rate and total smoke production of the PP compounds decreased significantly with the addition of small amounts of OMMT. The mechanical properties such as tensile and impact strength of the PP compounds decreased to some extent with the addition of talc, DBDPE and OMMT. These results demonstrated that the better flame retardant efficiency and mechanical properties could be obtained in virtue of the synergistic effect of talc, DBDPE and OMMT.