In the current study some information is presented about the distribution and associations between alfalfa aphids and their parasitoids in different regions in 11 provinces of Iran, as well as identification key to the parasitoids. The main aphids were Therioaphis trifolii maculata (Buckton) and Acyrthosiphon pisum (Harris) followed by Aphis craccivora Koch and Acyrthosiphon kondoi Shinji. The distribution pattern of these aphids showed a discrepancy in different regions. Therioaphis trifolii maculata was almost distributed in all studied areas, but A. craccivora mostly distributed in lower regions including the deserts of the east and central parts of Iran. Acyrthosiphon pisum and A. kondoi were mainly occurred inhigher altitude regions.Trioxys complanatus Quilis and Praon exsoletum (Nees) were found to be specific parasitoids of T.trifolii maculata, and collected, with a few exceptions, in all studied regions. The species of Acyrthosiphon were mainly attacked by Aphidius ervi Haliday followed by A. smithi Sharma & Subba Rao and A. eadyi Stary, Gonzalez & Hall. Lysiphlebus fabarum (Marshall) was the common parasitoid of A. craccivora, but Ephedrus persicae Froggatt locally found to show host specificity on this aphid. Praon volucre (Haliday) was occasionally found to attack A. pisum and A. craccivora, but the other parasitoids including Aphidius colemani Viereck, Lysiphlebus confusus Tremblay & Eady and Diaeretiella rapae (McIntosh) were only reared from A. craccivora. Considering the occurrence of alfalfa aphids together with their parasitoids in almost all studied areas, it seems that more attention should be paid to the parasitoids of alfalfa aphids, especially the specific ones, along with other control methods in an integrated pest management programme.