The biological characteristics related to the efficiency of natural enemies are considered as quality control indices, prior to release of biological control agents. In this research, biological parameters of Ooencyrtus egeria Huang and Noyes (Hymenoptera: Encyrtidae) an egg parasitoid of the green stink bug, Acrosternum arabicum Wagner (Hemiptera: Pentatomidae) was determined under laboratory conditions (27 ± 1 °C, 60 ± 5 % RH and 16:8 [L:D] h) using one-day-old eggs of host and in 10 replicates simultaneously. The result revealed that developmental time of egg, larvae of first to fifth instars, pre-pupal,pupal and total developmental time were 35.25±0.80, 96.75±1.89, 15.75±1.17,157.50±2.01 hours and 12.73±1.30 days respectively. Preoviposition period of mated and virgin females were obtained 21.8±0.36 and 21±0.42 hours, respectively. Longevity of virgin females and mean number of progeny were calculated 38.50±1.28 days and 169.97±1.80 eggs, in contrast mated females had lower longevity (34.50±2.33 days) and higher number of progeny (184.25±1.45 eggs). The highest level of egg laying occurred for mated females on the sixth day (22.50 ± 1.37) and for virgin females on the seventh day (17.64 ± 1.45) and terminated at 19 and 21 day for mated and virgin females, respectively. The sex ratio (female progeny to all population) was 0.73 in laboratory rearing and the virgin females produced only male offspring. No superparasitism was observed when had the enough eggs. Consequently, O. egeria may be considered as an effective biological control agent of the Pistachio green stink bug, although these results need to be confirmed by further field studies.