Poly(vinyl alcohol) sponges (P-sponges) have been used as a potential implant material for the replacement and repair of soft tissues, including cartilage, liver, and kidney. However, the application of P-sponges as tissue replacement materials is almost entirely bounded because of a lack of sufficient mechanical properties. In this study, we characterized the mechanical properties of a fabricated poly(vinyl alcohol) sponge (P-sponge) under a series of longitudinal and circumferential uniaxial loadings. The nonlinear mechanical behavior of the P-sponge was also computationally investigated with hyperelastic strain energy density functions, that is, the Ogden, Yeoh, Mooney–Rivlin, and Neo-Hookean models. A hyperelastic constitutive model was selected to best fit the axial behavior of the sponge. The results reveal that the Young's modulus and maximum stress of the P-sponge in the longitudinal direction were 16 and 17% greater than that in the circumferential direction, respectively. The Yeoh model, in addition, was selected to represent the nonlinear behavior of the poly(vinyl alcohol) material and could be used in future biomechanical simulations of the soft tissues. These results can be used to understand the mechanical properties of spongy materials in different loading directions. In addition, they have implications for ophthalmic and plastic surgeries and wound healing and tissue engineering purposes. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40257.