Electronic Journal of Differential Equations, Vol. 2009(2009), No. 151, pp. 1-18. Title: Lp-Regularity of solutions to first initial-boundary value problem for hyperbolic equations in cusp domains Authors: Nguyen Manh Hung (Hanoi National Univ., Vietnam) Vu Trong Luong (Taybac Univ., Sonla City, Vietnam) Abstract: In this article, we establish well-posedness and Lp-regularity of solutions to the first initial-boundary value problem for general higher order hyperbolic equations in cylinders whose base is a cusp domain. Submitted July 24, 2009. Published November 25, 2009. Math Subject Classifications: 35D05, 35D10, 35L30, 35L35, 35G15. Key Words: Hyperbolic equations; first initial-boundary value problem; Lp-regularity; cusp domain.