The effect of prior oviposition experience on the avoidance of superparasitism was investigated in the solitary endoparasitoid Fopius arisanus (Sonan) (Hymenoptera: Braconidae), a highly successful biological control agent of tephritid fruit fly pests. Individual female wasps, either naïve or having prior egg-laying experience in unparasitized hosts, were allowed to sequentially visit two coffee berries, each infested with a clutch of host eggs of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae). One of the two berries had been previously exploited by a conspecific female or the test-female herself. The wasp was allowed to visit the previously exploited or unexploited berry first while either in the presence or absence of a conspecific female. Naïve wasps readily accepted previously parasitized hosts only when they visited the previously exploited fruit first. In contrast, wasps that had experienced prior oviposition, and wasps that visited the unexploited berry first, never accepted previously parasitized hosts, even when the test wasps contained relatively high egg-load or had been exposed to hosts in the presence of conspecific females. These results demonstrate a dramatic effect of egg-laying experience on the avoidance of superparasitism by this parasitoid. We discuss the adaptive value of avoiding superparasitism in relation to the mechanism of intraspecific competition in this species.