Keys and diagnoses of North European aphids (Hemiptera, Aphidoidea) feeding on conifers are given, including species from nearby areas of Central and Western Europe, based on live and freeze-dried material. Externally visible informative characters, such as body shape, colours, wax coating, and pigmentation pattern are utilized, in addition to characters traditionally used in the literature. Rich ... [Show full abstract] illustrations with photographs of live colonies and freeze-dried specimens, supported by drawings where needed, are presented. The combination of colour images and diagnoses, utilizing easily observed characters, allows the identification of a large number of species already in the field, and many more at home with the aid of a stereo microscope. Host plant relationships and aphid-ant associations are presented.