We discuss the nature of the pairing mechanism and the physical properties associated with the normal as well as the superconducting state of cubic perovskites Ba 0.6 K 0.4 BiO 3 using the strong coupling theory. An interaction potential which includes the Coulomb, electron-optical phonon and electron-plasmon interactions is developed to elucidate the superconducting state. A model dielectric function is constructed with these interactions fulfilling the f -sum rule. The screening parameter (µ * = 0.26) infers the poor screening of charge carriers. The electron-optical phonon strength (λ) estimated as 0.98 is consistent with an attractive electron-electron interaction and supports the moderate to strong coupling theory. The superconducting transition temperature of Ba 0.6 K 0.4 BiO 3 is then estimated as 32 K. Ziman's formula of resistivity is employed to analyse and compare this with the temperature-dependent resistivity of a single crystal. The estimated contribution from the electron-optical phonon together with the residual resistivity clearly infers a difference when a comparison is made with experimental data. The subtracted data infer a quadratic temperature dependence in the temperature domain (30 ≤ T ≤ 200 K). The quadratic temperature dependence of ρ [= ρ exp -(ρ 0 +ρ e-ph )] is understood in terms of 3D electronelectron inelastic scattering. The presence of these el-el and el-ph interactions allows a coherent interpretation of the physical properties. Analysis reveals that a moderate to strong coupling exists in the Ba 0.6 K 0.4 BiO 3 system and the coupling of electrons with the highenergy optical phonons of the oxygen breathing mode will be a reason for superconductivity. The implications of the above analysis are discussed.