Objectives: The articulating surfaces of the temporomandibular joint are covered with fibrocartilage rather than hyaline cartilage in most other synovial joints. Articular cartilage in the TMJ is a viscoelastic material consisting of two principle phases: a solid matrix phase composed mainly of collagen and proteoglycan, and a predominant interstitial fluid phase. This study determined biphasic viscoelastic properties of porcine TMJ condyle cartilage. The regional variation in mechanical properties was investigated. Methods: Eight porcine TMJs from young adult pigs (~85Kg) were used for this study. Cartilage plugs (5mm diameter) were excised from six regions (lateral, intermediate, and medial at anterior/posterior) of each condyle head. The deep zone of each plug was removed to ensure a uniform thickness. Each specimen was subjected to a 5% offset strain, followed by a 2-hour creep test in a confined compression mode. The equilibrium aggregate modulus and hydraulic permeability were obtained by curve-fitting creep data to the biphasic theory develop by Mow et al. (1980). One-way ANOVA and Bonferroni adjustment were used to analyze the effect of region on material properties. Results: The value of aggregate modulus of porcine condyle cartilage is 37.8±16.4 kPa, which is much smaller than that of the human knee joint cartilage (6%). The hydraulic permeability value is 1.44±0.56x10-13m4/Ns, which is about two orders of magnitude higher than that of human knee joint cartilage. The intermediate site is the softest, and the medial region is the least permeable. Conclusion: The biomechanical properties of the TMJ condyle cartilage are significantly different from those of cartilage present in other diarthrodial joints. Significant differences in biomechanical properties exist in various region of the TMJ condyle cartilage. Our results suggest that the function of fibrocartilage in the TMJ condyle is substantially differently from that of hyaline cartilage in other joints. (Supported by NIH 5U24DE016508).