Abstract: The tomato leaf miner Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is the most damaging pest for tomato plants of both fields and greenhouses. The present study aimed at evaluating the effect of microclimate on Trichogramma dispersal in greenhouses submitted to two different overall climates to control the tomato leaf miner, T. absoluta. Two Trichogramma species, T. euproctidis Girault and T. achaeae Nagaraja & Nagarkatti, were tested using six greenhouse trials, three per each climatic condition. These latter trials consisted of releasing T. euproctidis at a rate of 50 adults/m² or T. achaeae at a rate of 50 adults/m² and no parasitoids for the control trial. This experiment took place in protected tomato cultivations during the winter plantation 2014-15 at Berqash district, Giza, Egypt. The obtained results indicated that both parasitoids, T. euproctidis Girault and T. achaeae Nagaraja & Nagarkatti, were significantly efficient in keeping down T. absoluta mines, especially at high relative humidity.