The Citrus leaf-miner, Phyllocnistis citrella (Stainton) (Lepidoptera: Gracillariidae), first detected in La Reunion in 1995, rapidly spread to the whole island within a few months. During the following years, studies on the natural enemies complex of the leaf-miner showed the presence of five species of indigenous parasitoids (Hymenoptera: Eulophidae), with two species generally dominating : Neochrysocaris sp. and Sympiesis sp. However; during the following years, surveys on parasitism rates showed that indigenous parasitoids could not, in most cases, effectively control the leaf-miner populations. So, a biocontrol programme was initiated in 1998, in collaboration with INRA Antibes, in order to acclimatize the exotic ovo-pupal parasitoid Ageniaspis citricola Logvinovskaia (Hym. : Encyrtidae). A small-scale rearing was set up and releases made in a few suitable orchards in 1998-1999. A study on the evolution of leaf-miner populations and status of parasitism was carried out in 1999-2000. The seasonal variations of the leaf-miner populations were linked with vegetative flushes and the occurrence of other pests occupying a similar ecological niche (aphids, whiteflies). In 2000, A. citricola was detected in various localities, which confirmed the success of the acclimatisation programme. During recent years, damage caused the leaf-miner has been limited which is probably due to an improved biological equilibrium between the pest and its natural enemies. Future studies should focus on a better quantification of the impact of A. citricola.