The cowpea aphid, Aphis craccivora Koch. is the most common species attacks leguminous crops in Egypt. Among the parasitoid spe­cies which attack A.craccivora on faba bean was the braconid parasitoid, Lysiphlebus faberum Marchall. Morphological and biological studies on the parasitoid species were conducted under the laboratory conditions, 20⁰D and 70% R.H. Egg, larva, pupa and adult of the parasitoid were de­scribed. Biological studies included duration of immature stages, emer­gence process of the parasitoid adult, mating behavior, egg-laying pro­cess, adult longevity and sex ratio. Duration Of Liabarum immature stages averaged 0.4 t 0.03. 5.2 t 0.2 and 4.1 t 0.1 days under labora­tory conditions for the incubation period, larval and pupal periods, re­spectively. Adult longevity lasted 1.9 ± 0.1 and 4.1 t0.2 days for male and female, respectively. Sex ratio was estimated as 1:2.8 Cif_q_ under the laboratory conditions.