Abstract: The California red scale, Aonidiella aurantii (Maskell) (Hemiptera: Diaspididae),is probably one of the most important citrus pests in the world. The damage is produced bysucking the sap from any plant organ that, in extreme cases, can even kill the tree. Thecontrol of diaspidids in Spain has been usually based on the application of large-spectrumpesticides, as organophosphates alone or in mixture with mineral oils. In the recent yearsenvironmentally safer measures as augmentative biological control are being encouraged. Tothis end, the knowledge of the impact of the indigenous natural enemies on this pest is anessential requisite to know. In this work, natural mortality factors such as parasitism, hostfeeding and predation have been studied in different non-treated orchards located, inValencia and in Castellón de la Plana from 2007 to 2009. The levels of natural mortality onA. aurantii rarely were higher than 40 %, values that unfortunately were not sufficient toguarantee a good control. The mortality due to parasitism was higher than the one caused bypredation. A significant preference by the third nymphal instar was observed for bothmortality factors. Host feeding on A. aurantii nymphal instar was also observed, althoughmost of the scales remained alive. Feeding punctures were also found mainly on the thirdnymphal instars. The parasitoids species detected on A. aurantii were by order of importanceAphytis melinus DeBach and A. chrysomphali (Mercet) (Hymenoptera: Aphelinidae).