The effect of high hydrostatic pressure (HHP) treatments on chemical composition, proteolysis, rheological properties, total free amino acids and organoleptic properties for Cheddar cheese during ripening at 8-10^oC up to 120 days were evaluated. Application of HHP-treated Cheddar cheese at three levels (200, 400 and 600 MPa at 25^oC for 20 min.) was carried out as a methods for acceleration of Cheddar cheese ripening. Results showed that HHP-treated at 600 MPa for 20 min. at 25^oC was significantly higher in moisture, fat in dry matter and pH values, on the other hand total solids, was significantly lower throughout the ripening period followed by cheeses treated at 400, 200 MPa for 20 min. and control cheeses, respectively. All Cheddar cheeses treated with HHP showed significant (P≥0.05) higher increase in nitrogen fractions (WSN/TN% and NPN/TN%) than control cheese during ripening up to 120 days. Morover, total volatile fatty acids was significantly higher (P≥0.05) in cheese treated at 600 MPa than other cheeses during ripening. Rheological properties indicated that, HHP-treated Cheddar cheese at 600 MPa for 20 min. The significant lower (P≥0.05) values of hardness as compared to cheese treated at 200, 400 MPa and control cheeses. lowest values of chewiness and gumminess were observed in cheese treated at 200 and 400 MPa at the end of ripening. Also, HHP-treated Cheddar cheese at 600 MPa had a higher levels of total free amino acids than other cheeses treated at 200, 400 MPa and control cheeses,. HHP-treated Cheddar cheeses gained significantly higher flavour and texture scores compared to control cheese, but HHP-treated Cheddar chees at 600 MPa for 20 min. showed higher total scores than other cheese treatments.