Abstract: During the biennium 2009-2010, a survey on the pest status of some ant species wasconducted in some cork-oak stands of the North of Sardinia. In the first year, 5 species ofarboricolous ants were collected by direct sampling from a number of trees randomly chosen.Although they are not very common species, workers of Camponotus fallax (Nylander, 1856) andCamponotus truncatus (Spinola, 1808) were collected inside little twigs and in other refuges.Crematogaster scutellaris (Olivier, 1792) was the most common species as its presence wasdetected in every tree. Camponotus vagus (Scopoli, 1763) was observed primarily in old treesand in rotten wood among roots and its pest status has not been seen yet as it rarely builds its nestin productive trees. Serious damages caused by Lasius brunneus (Latreille, 1798) were observedon cork bark of young plants. The ant activity degrades cork, diminishing its market value andmakes the extraction of the cork very difficult. As a consequence, in the second year the surveyof ant fauna was replicated in the same site by using also pitfall traps and carried out in threeother plots. The infestation percentage caused by L. brunneus was estimated as well as thedamage on each plant.