The present invention relates to conjugated linoleic acid (CLA)-producing strains of probiotic bacteria. In particular, the present invention relates to a selection of bacterial strains belonging to the genus Bifidobacterium which were selected for their ability to produce conjugated linoleic acid (CLA) from linoleic acid (LA). Furthermore, the present invention relates to a food, dietetic or pharmaceutical composition comprising said bacterial strains capable of increasing the quantity of CLA in situ, i.e. inside the gastrointestinal tract.