This study was carried out to evaluate the possibility of increasing the presence of selected yeasts in freshly produced extra-virgin olive oil by inoculating olives prior to processing. New types of yeasts, classified as Williopsis californica and Candida boidinii, were found. A beta-glucosidase producing strain of W. californica, used as starter in the olive inoculation trials, was able to increase the amount of oleuropeinolytic yeasts in olive oil during the whole sedimentation period. The increase of yeasts in olive oil, compared to the uninoculated control, was 20 and 30%, respectively, for the continuous and discontinuous system used for processing the olives. The inoculation of the olives with selected yeasts was demonstrated to be a valid technique to enrich oil with useful microorganisms without directly manipulating the product.