We prove uniqueness of positive solutions for the system Delta u = -lambda f(nu), Delta nu = -mu g(u) in Omega, u = v = 0 on partial derivative Omega, where Omega is a bounded domain in R-N, f,g: R+ -> R+ and f(x) similar to x(p), g(x) similar to x(q) at infinity for some positive numbers p, q with pq < 1. (c) 2005 Elsevier Inc. All rights reserved.