The radiation-resistant response of BaTiO3 in the tetragonal and rhombohedral phases on exposure to 100MeV Ag7+ ion irradiation was investigated by insitu X-ray diffraction (XRD) at room temperature (300K) and low temperature (25K), respectively. This study revealed that the BaTiO3 in rhombohedral phase retained crystallinity up to an ion fluence of 1x10(14)ions/cm(2), whereas tetragonal phase amorphized at much lower fluence viz. 1x10(13)ions/cm(2). The insitu XRD along with Raman spectroscopy studies revealed that BaTiO3 in rhombohedral phase is more radiation resistant than that of tetragonal phase. The density functional theory (DFT) calculations confirmed higher bond strength of rhombohedral phase as compared to tetragonal phase, which supported the experimental result of higher radiation stability of rhombohedral phase. The theoretical predictions on high-temperature phase will be of relevance to the nuclear waste applications.