Due to their biodegradability and biocompatibility through non toxic intermediates, PHBV and PLA are considered as ideal candidates to replace non biodegradable polymeric materials, in particular for short-term applications. Moreover, they can be processed in conventional equipment as those used for synthetic polymers. On the other hand, there has been significant interest in the gamma sterilization of polymers being used in some technological fields like biomedical and food packaging to ensure microbiological safety. However, it is known that γ-irradiation may cause some undesirable effects on polymers. Therefore, it becomes necessary to study the chemical and physical effects that are induced by the transfer of energy to the polymer. Therefore, this paper aims to study the effects of gamma irradiation on the morphology and physical properties of various blends based on PHBV and PLA : 50/50 w/w with and without PHBV-g-MA and organo-modified montmorillonite used as the compatibilizer and reinforcement agent, respectively. Blend compositions were prepared by melt compounding and compression molded to thin films of an average thickness of 150 µm. The different samples were subjected to 25, 50 and 100 kGy at room temperature; the dose rate being 1.0 Gy/h. The study showed through FTIR spectra analysis the occurrence of some chemical modifications in the irradiated samples, in particular at absorbed dose of 100 kGy resulting in the formation of a large absorption band in the carbonyl region. Size exclusion chromatography data showed a decrease in the average molecular weight for all irradiated samples with increasing the absorbed dose due to chain scission mechanism. Nanoindentation test showed that ɣ- irradiation significantly decreased both modulus and hardness of neat PHBV and neat PLA after 100 kGy, whereas no noticeable changes were observed for PHBV/PLA blends. TGA and PCFC test revealed that a good compatibilization owing to the presence of the organomodified clay can compensate the effect of irradiation on both thermal stability and fire retardancy of PHBV/PLA blends.