Electronic Journal of Differential Equations, Vol. 2007(2007), No. 15, pp. 1-6. Title: Viscosity solutions to degenerate diffusion problems Authors: Zu-Chi Chen (Univ. of Science and Technology, Hefei, China) Yan-Yan Zhao (Univ. of Science and Technology, Hefei, China) Abstract: This paper concerns the weak solutions to a Cauchy problem in $R^N$ for a degenerate nonlinear parabolic equation. We obtain the Holder regularity of the weak solutions to this problem. Submitted November 4, 2006. Published January 23, 2007. Math Subject Classifications: 35K15, 35K55, 35K65. Key Words: Viscosity solution; degenerate; Holder regularity.