In this study, in order to investigate atmospheric instability conditions, thermodynamic indices such as Convective Available Potential Energy, Total Totals Index and dynamic indices including Eady growth rate and bulk wind shear are calculated using JRA-55 data with 1.25 ° separation in zonal and meridional directions during the period 1958 to 2021. Then, the distribution of atmospheric stability indices during El Niño Southern Oscillation phases is climatologically investigated over West Asia and Iran. The results show that atmospheric instability conditions in West Asia and Iran increase during El Niño compared to La Niña due to increase in mid-tropospheric humidity and the changes in the temperature structure.