Mediteranean fruit fly (MFF), Ceratitis capitata, Wiedemann (Diptera: Tephritidae) is one of the most important  pests destructing guava fruits. The present work aimed to study  the adult activity of MFF using two sample methods and correlating the numbersof adults of MFF with Temperature and Relative humidity at El- Dakahlia and Kafr El-Shaikh  Governorates during 2019and 2020 seasons. The obtained results indicated that MFFadults populations showed three distinct peaks at El- Dakahlia and Kafr El-Shaikh  Governorates. The obtained results indicated that MFF recorded two peaks of the mean of infection per fruit and infection percentage, the first season at 15 August (4.43, 19.5%) and 22 August (4.76, 20.32). While in the second season recorded two peaks at (6 and 13 September ) the percentage of infections were (19.67% and 22.65%) respectively. The MFF population exhibited insignificant and significant correlation coefficients with temperature in the first (r=-0.20) and  second (r=0.87) seasons, whereas the population showed insignificant response to relative humidity at El-Dakahlia and Kafr El-Shaikh Governorates.