In this study, effects of high pressure (HP) on some constituents and properties of buffalo milk were examined. HIP treatment at 100-600 MPa for 30 min affected casein micelle size only slightly, whereas treatment at 800 MPa increased it by &SIM; 35%. Levels of non-micellar as and β-caseins were increased by treatment > 250 MPa, and were highest after treatment at 400-80OMPa. The level of non-micellar calcium increased with increasing pressure up to 600 MPa. The L*-value of the milk decreased gradually with increasing pressure, from &SIM; 82 for untreated milk to &SIM; 65 for milk treated at 800 MPa. Milk pH was increased by &SIM; 0(.)07 units after treatment at 100-800 MPa, with no significant difference between treatment pressures. Denaturation of α-lactalbumin occurred at pressures &GE; 400 MPa, and reached > 90% after treatment at 800 MPa, whereas β-lactoglobulin (β-Ig) was denatured > 100 MPa, reaching &SIM; 100% after treatment at 400 MPa; after treatment &GE; 400MPa, all β-Ig was associated with the casein micelles. The rennet coagulation time of buffalo milk increased with increasing pressure, whereas the strength of the coagulum formed decreased after treatment at 250-800 MPa. Overall, HP treatment affected many constituents and properties of buffalo milk; some of these effects have also been observed in the milk from other species, but the extent of the effects, and the pressure at which they occurred, differed considerably.