Electronic Journal of Differential Equations, Vol. 2002(2002), No. 99, pp. 1-20. Title: A note on a Liouville-type result for a system of fourth-order equations in R^N Authors: Ana Rute Domingos (Univ. de Lisboa, Portugal) Yuxia Guo (Tsinghua Univ., Beijing, China) Abstract: We consider the fourth order system $\Delta^2 u =v^\alpha,\Delta^2 v =u^\beta$ in $\mathbb{R}^N$, for $N\geq 5$, with $\alpha\geq 1$, $\beta\geq 1$, where $\Delta^2$ is the bilaplacian operator. For $1/(\alpha +1) +1/(\beta +1)>(N-4)/N$ we prove the non-existence of non-negative, radial, smooth solutions. For $\alpha,\beta\leq (N+4)/(N-4)$ we show the non-existence of non-negative smooth solutions. Submitted November 27, 2001. Published November 27, 2002. Math Subject Classifications: 35J60. Key Words: Elliptic system of fourth order equations; moving-planes.