Beni-suef combined cycle power plant (CCPP) is one of the largest and most advanced power plants in Egypt and even in the world. It is equipped with four units (modules). Each unit consists of two gas turbines (GT), two triple pressure heat recovery steam generators (HRSG), one steam turbine (ST) and three generators. The power plant has a rated net electrical output of approximately 4800 MW (1200 MW/module) with efficiency exceeds 60% at its site design conditions. The performance of any combined cycle power plant (CCPP) is influenced by the ambient conditions of the place where it is installed like ambient temperature, atmospheric pressure, air relative humidity and cooling water inlet temperature. This study aims to investigate the effect of ambient temperature and air relative humidity on the performance of Beni-suef combined cycle power plant (CCPP) by performing an energy and exergy analysis of the combined cycle power plant components. Energy and exergy analysis were performed at 16.1, 28.1, 37.6 ^oCambient temperatures for the components of one module of Beni-suef combined cycle power plant using the in-operation data. Also, the effect of air relative humidity ratio was studied on the gas turbine performance at 16.1, 28.1, 37.6 ^oC ambient temperatures and different relative humidity ratios from 10 to 90%.