During a 2-yr survey of Kauai Island, four species of opiine parasitoids were recovered from host fruits infested withBactrocera dorsalis(Hendel) [=Dacus dorsalisHendel];Biosteres arisanus(Sonan),Diachasmimorpha longicaudata(Ashmead),Psyttalia incisi(Silvestri), andBiosteres vandenboschi(Fullaway). These species constituted 87.5, 9, 2.4, and 1.1% of the total parasitoids recovered in 1988, and 95.1, 0.9, 4, and 0.04% of the total parasitoids recovered in 1989, respectively. Total islandwide opiine parasitism rates on the basis of live parasitoids recovered from oriental fruit fly pupae were 41.4% in 1988 and 53% in 1989. Wild common guava,Psidium guajavaL., and strawberry guava,Psidium cattleianumSabine, were the most prevalent hosts infested with oriental fruit fly encountered during our roadside survey. Population studies in a large commercial common guava orchard indicated that oriental fruit fly infestation of fruits was correlated with infestation of wild common guava fruits in surrounding wild habitats. Positive correlations between numbers ofB. arisanus, the dominant parasitoid, and numbers of oriental fruit fly indicated a density-dependent relationship. Overall, percentage parasitism ofB. arisanuswas significantly higher in wild habitats than in orchard habitats. Relative abundance ofD. longicaudata, P. incisi, andB. vandenboschiwere significantly higher in orchard habitats than in wild habitats.