The parasitoid complex of Saperda populnea (L.) (Col., Cerambycidae) was studied during the period 2002-2003 at different sites in Bulgaria. Galls containing cerambycid larvae were collected on branches of aspen (Populus tremula L.), goat willow (Salix caprea L.) and hybrid poplars and were studied under laboratory conditions. As a result, four new species for the parasitoid complex of S. populnea in Bulgaria were recorded: Dolichomitus tuberculatus (Geoffroy), Xylophrurus lancifer (Gravenhorst), Gelis ornatulus (Thomson) (Hym., Ichneumonidae) and Dendrocerus serricornis (Boheman) (Hym., Megaspilidae). D. serricornis and G. ornatulus are new species for Bulgarian fauna. D. tuberculatus and X. lancifer were found as primary parasitoids, and G. ornatulus and D. serricornis as hyperparasitoids. The primary parasitoids developed solitarily in the host larvae. D. serricornis was reared gregariously from a puparium of Billaea irrorata (Meig.) (Dipt., Tachinidae). The host of G. ornatulus was not identified, but the hyperparasitid could be connected with Iphiaulax impostor (Scop.) (Hym., Braconidae). The mortality of S. populnea caused by the parasitoids was 2.0-6.3%. Parasites diseases and disorders; Parasites; Insect parasites; Hosts; Insect hosts; Land zones; Palaearctic region; Eurasia; Europe Saperda populnea (Cerambycidae); Dipteran parasites; Billaea irrorata; Hymenopteran parasites; Iphiaulax impostor; Probable hyperparasitism recorded; Dolichomitus & Xylophrurus; Plant hosts; Populus & Salix caprea; Hyperparasitism; Bulgaria; Parasites & hyperparasites recorded including new record & probable record Billaea irrorata (Tachinidae); Hymenopteran parasites; Dendrocerus serricornis; Coleopteran hosts; Saperda populnea; Hyperparasitism; Recorded; Bulgaria; Hyperparasitism recorded, hymenopteran parasite & coleopteran host Iphiaulax impostor (Braconidae); Hymenopteran parasites; Gelis ornatulus; Coleopteran hosts; Saperda populnea; Hyperparasitism; Bulgaria; Probable hyperparasitism recorded, hymenopteran parasite & coleopteran host Dolichomitus tuberculatus; Xylophrurus lancifer (Ichneumonidae ); Coleopteran hosts; Saperda populnea; New host record, plant host; Bulgaria; New coleopteran host record Gelis ornatulus (Ichneumonidae); Hymenopteran hosts; Hyperparasitism; Bulgaria; Probable hyperparasitism recorded Dendrocerus serricornis (Ceraphronidae); Dipteran hosts; Billaea irrorata; Hyperparasitism; Bulgaria; Recorded, dipteran & hymenopteran hosts none