The scarce swallowtail butterfly, Iphiclides podalirius feisthamelii (Duponchel), is oligophagous and feeds on woody plants of the Rosaceae family. In north-east Spain it has a bivoltine life cycle, with a third partial generation greatly overlapped with the second. Overwintering occurs in the pupal stage. Between 1996 and 1999, survivorship of immature stages was studied in a typical habitat. Eight species of parasitoids were found in association with the butterfly, from a sample consisting of over 1000 eggs, 124 larvae and 32 pupae. Anastatus bifasciatus (Geoffroy) (Hymenoptera: Eupelmidae), Ooencyrtus telenomicida (Vassiliev) (Hymenoptera: Encyrtidae), Trichogramma cordubensis Vargas and Cabello and Trichogramma gicai Pintureau and Stefanescu (Hymenoptera: Trichogrammatidae) regularly attacked the second and third generations, causing mortalities ranging from 25 to 45% of the host eggs. Compsilura concinnata (Meigen) (Diptera: Tachinidae) was also regularly recorded attacking 0-20% of the larvae of the summer (second and third) generations. On the other hand, incidence of parasitism was extremely low during the first generation and consisted mainly of single records of adventitious parasitoids (Ooencyrtus vinulae (Masi) (Hymenoptera: Encyrtidae), Meteorus pulchricornis (Wesmael) (Hymenoptera: Braconidae), Blepharipa pratensis (Meigen) (Diptera: Tachinidae)). No pupal parasitism was detected, though the sample size was small. The parasitoid complex of I. podalirius consisted almost exclusively of broadly generalist species that can also attack several important Mediterranean forest pest Lepidoptera, which makes the phenomenon of apparent competition between alternative hosts highly likely. Finally, diagnostic biometric measurements of parasitoid emergence holes from the host egg and details of the life history of the main parasitoids are provided. Parasites diseases and disorders; Parasites; Insect parasites; Hosts; Insect hosts; Ecology; Land and freshwater zones; Palaearctic region; Europe Tachinidae; Hymenoptera; Lepidopteran hosts; Iphiclides podalirius feisthamelii; Parasite assemblage & effects on host population dynamics; Community structure; Spain; Catalonia; Can Liro & Can Riera de Vilardell; Lepidopteran host assemblage & effects on host population dynamics Iphiclides podalirius feisthamelii (Papilionidae); Dipteran parasites; Tachinidae; Hymenopteran parasites; Parasite assemblage & effects on host population dynamics; Population dynamics; Spain; Catalonia; Can Liro & Can Riera de Vilardell; Insect parasite assemblage & effects on host population dynamics none