Sixth Mississippi State Conference on Differential Equations and Computational Simulations. Electronic Journal of Differential Equations, Conference 15 (2007), pp. 229-238. Title: Global attractivity in a nonlinear difference equation Authors: Chuanxi Qian (Mississippi State Univ., MS, USA) Yijun Sun (Mississippi State Univ., MS, USA) Abstract: In this paper, we study the asymptotic behavior of positive solutions of the nonlinear difference equation $$ x_{n+1}=x_n f(x_{n-k}), $$ where $f:[0,\infty)\to(0, \infty)$ is a unimodal function, and $k$ is a nonnegative integer. Sufficient conditions for the positive equilibrium to be a global attractor of all positive solutions are established. Our results can be applied to to some difference equations derived from mathematical biology. Published February 28, 2007. Math Subject Classifications: 39A10. Key Words: Nonlinear difference equation; global attractor; unimodal function; positive equilibrium.