The aim of research was establishing of aphids damaging the hazel trees in Azerbaijan, their entomophaghs, studying of their bioecological abilities. The paper was prepared on the basis of results of researhces carried out in Ismayilli, Gabala and Zagatala districts in 2017-2018. Research was carried out on single hazelnut bushes growing in parks and orchards of Baku and Absheron, and in hazelnut orchards and forests of Ismayilli, Gabala and Zagatala districts in 2017-2018. Field works were carried out twice in a month along the route and each week in the stationaries. In the areas containing 50 hazel bushes 15-20 bushes were surveyed, and 25-30 bushes were surveyed in orchards with more than 100 bushes. Samples for revealing the hazel pests were taken in 10 points in the 20 hectare area. Damage percent, intensity of damage, accurate number of aphids were calculated on 20 bushes. The number of aphids per bush calculated by five-point scale: 0 point means no aphids on the hazelnut, 1 point when there single individuals on leaves, 2 points mean that there are 1-2 colonies and 5-10 aphids per colony, 3 points mean that 50% of leaf blade was occupated and there are more than 20 aphids per collony, 4 point mean that 75% of leaf blade was occupated and there are more than 50 aphids per collony and 5 points mean that aphid colony occupied the whole area of the leaf blade. The populations of the aphids are managed by predators: Adalia bipunctata (Linnaeus, 1758), Adalia decempunctata (Linnaeus, 1758), Coccinella septempunctata (Linnaeus, 1758), Oeponia conglobata L., Harmonia axyridis (Pallas, 1773), Calvia decemguttata (Linnaeus, 1767), Propylea quatuordecimpunctata (Linnaeus, 1758) from Coccinellidae, Chrysoperla carnea (Stephens, 1836) from Neuroptera, Phyus coryli (Linnaeus, 1758) from Hemiptera, Clanoptilus sp. from Melyridae and Forficula auricularia (Linnaeus, 1758) from Forficulidae. Chemicals are usually not required. The hazelnut pest Myzocallis coryli was recorded in all studied areas: along Shaki-Zagatala motorway edge, in the Mughanli and Kebeloba villages of Zagatala district and in the Baku-Absheron area. Corylobium avellanae was found along Shaki-Zagatala motorway edge and Mughanli village of Zagatala district. Entomophags Adalia bipunctata, Adalia decempunctata, Coccinella septempunctata, Harmonia axyridis, Chrysoperla carnea, Forficula auricularia also were recorded everyware in studied areas, however Oeponia conglobata, Calvia decemguttata -along Shaki-Zagatala motorway edge, Propylea quatuordecimpunctata -along Shaki-Zagatala motorway edge, Mughanli village of Zagatala district and Phyus coryli, Clanoptilus sp. in the all studied area except Baku-Absheron peninsular.