Krk cheese is a hard, full-fat cheese made from raw sheep's milk, characterized by a delicate, full and strong flavour. The aim of this study was to determine farm influence on the chemical composition of sheep's milk for Krk cheese production, and the chemical characteristics of Krk cheese during ripening. Gross composition of the milk used complies with the average sheep's milk composition from the Croatian Adriatic region. During ripening, fat, protein, salt content and lactic acid concentration increased (P < 0.01), as well as the water-soluble nitrogen fraction and the 12%-trichloroacetic-acid-soluble nitrogen fraction (P < 0.05). Degradation of β-casein could be an indicator of the ripening quality of Krk cheese.