not in Young The cynipid gall wasps (Hym., Cynipidae) are among the main insects associated with oaks (Quercus sp.) in Iran. The objective of this study was to infer the inquiline species and the parasitoids associated with the cynipid gall wasps while determining species richness of gall wasps in oak forests of Kurdistan, Ilam and Kermanshah provinces in the west of Iran. The cynipid gall wasps were collected from buds and leaves of Quercus infectoria Olivier and. Q. brantii Lindley during 2004-2006. The collected galls were maintained under laboratory conditions at room temperature (20-25 [degree]C) in transparent plastic boxes until the cynipids, inquilines and their parasitoid adults were emerged, As a result of this study, 28, 22 and 4 gall wasp species were collected in Kurdistan, Kermanshah and Ilam provinces, respectively. Five species of inquiline cynipids were reared from gall inducer wasps: Synergus umbraculus (Olivier), S. mikoi Melika & Pujade-Villar, S. acsi Melika & Puj! ade-Villar, S. bechtoldae Melika & Pujade-Villar and Saphonercus irani Melika & Pujade-Villar. Three parasitoid species include Glabobracon variator Nees, Ascogaster quadridentata Wesmael and Bassus tumidulus (Nees) (Hym., Braconidae) reared from Pammene amygdalana (Duponchel) (Lep., Tortricidae) as inquiline species in oak galls related with Andricus cecconi Kieffer and A. multiplicatus Giraud. All three braconid species are reported here for the first time from Iran, The expected number of oak gall wasp species on Q infectoria and Q. brantii was estimated to be 16 and 6, respectively. Species richness and geographical distribution of oak gall wasps, their inquilines and parasitoids are given and discusse Cynipidae (Cynipoidea): Parasite; Andricus cecconi (Cynipidae); Andricus multiplicatus (Cynipidae); Saphonecrus irani (Cynipidae); Synergus acsi (Cynipidae); Synergus bechtoldae (Cynipidae); Synergus mikoi (Cynipidae); Synergus umbraculus (Cynipidae); Ascogaster quadridentata (Braconidae): Parasite; Bassus tumidulus (Braconidae): Parasite; Bracon variator (Braconidae): Parasite; Pammene amygdalana (Tortricidae): Host. Andricus cecconi, Andricus multiplicatus: Mutualism, Pammene amygdalana (Lepidoptera), New hymenopteran parasites on inquiline, Iran, Lepidopteran mutualists; Ascogaster quadridentata, Bassus tumidulus, Bracon variator: Lepidopteran hosts, Pammene amygdalana, New record, inquiline in hymenopteran gall, Iran; Cynipidae: Mutualism, Saphonecrus irani (Hymenoptera), Inquilinism, Synergus acsi (Hymenoptera), Synergus bechtoldae (Hymenoptera), Synergus mikoi (Hymenoptera), Synergus umbraculus (Hymenoptera), Plant hosts, Quercus brantii, Associated insect inquilines and parasites, Quercus infectoria, Species diversity, Iran, Kurdistan, Ilam and Kermanshah, Hymenopteran mutualists, distribution; Pammene amygdalana: Mutualism, Andricus cecconi (Hymenoptera), Inquilinism, new hymenopteran parasites, Andricus multiplicatus (Hymenoptera), Hymenopteran parasites, Ascogaster quadridentata, New record, Bassus tumidulus, Bracon variator, inquiline in hymenopteran gall, Iran, Hymenopteran mutualists; Saphonecrus irani, Synergus acsi, Synergus bechtoldae, Synergus mikoi, Synergus umbraculus: Mutualism, Cynipidae (Hymenoptera), Inquilinism, Iran, Kurdistan, Ilam and Kermanshah, Hymenopteran mutualists. Arthropods; Hymenopterans; Insects; Invertebrates; Lepidopterans. none2008checked