Observations were carried out in apple orchards and nurseries of the Plovdiv region (Central-South Bulgaria), aimed at determining specific composition, population density and economic importance of particular species of aphids, in the years 2004–2006. By surveys, carried out at 15-day intervals, the appearing species were identified and the degree of damage determined. Six species of aphids were found: Aphis spiraecola Patch., A. pomi Deg., Dysaphis plantaginea Pass., D. devecta Wlk. Rhopalosiphum insertum Wlk. and Eriosoma lanigerum Hsm. A. spiraecola, a poliphagous pest, was probably brought with the plant material from Greece and was identified in Bulgaria for the first time. It is similar to A. pomi and may be distinguished only by the microscopic investigation. Aphis spiraecola replaced almost completely A. pomi in the region studied. Its population was particularly high in nurseries. In the bearing orchards D. plantaginea was the most important aphid. Some tendency to an increase of population and damage caused by D. devecta was also noted. The other species had not any economic importance. E. lanigerum was present only in the orchards where no chemical control was applied.