In this study, the influence of rennet concentration on chemical composition, proteolysis and sensory properties of Halloumi cheese was evaluated during ripening. Halloumi cheese was manufactured from raw cow's milk using four levels of rennet (0.2, 0.25, 0.3 or 0.4 g rennet/kg cheese milk) and was ripened for 60 days at 4C. Proteolysis in the cheese was measured by determining soluble nitrogen fractions both in water and in 12% trichloroacetic acid as well as by patterns of urea-polyacrylamide gel electrophoresis. Cheese grading was performed by an expert panel throughout the ripening period. The chemical composition of the cheese was significantly influenced by the level of rennet, which could be related to the differences in moisture contents of the cheese. The levels of water- or 12% trichloroacetic acid-soluble nitrogen fractions and degradations of alpha(s1)- or beta-caseins were quite low during the cheese maturation. No relation was found between rennet concentrations and casein degradation in the cheese during ripening. Results indicated that the different concentrations of rennet did not significantly influence the proteolytic profiles and sensory scores of Halloumi cheese; that is, an amount of rennet between 0.2 and 0.4 g rennet/kg cheese milk resulted in a similar quality of Halloumi cheese.