|I will talk about the importance of cross section in the study of neutrino event rates. What are the different reactions contributing to the cross section at the energies of accelerator(mainly MiniBooNE & T2K) and the atmospheric neutrinos. How does the nuclear effect modifies the free nucleon cross section in nuclei. I will discuss the results of quasielastic, one pion, one kaon and the cross section for the deep inelastic scattering. Some of the results I will compare with the latest results from K2K, MiniBooNE and other experiments for QE and one pion and with NuTeV, CHORUS, etc experiments for the DIS process.