Numeration, isolation and identification of the lactic acid bacteria found in Asturian cider during processing and storage has been carried out. The species Leuconostoc oenos was predominant during both alcoholic and malolactic fermentations. In most of the ciders studied the malolactic fermentation and the alcoholic fermentation started at the same time; production af D-lactate as well as a decrease of L-lactate were to be found once the malolactic fermentation was complete.