Electronic Journal of Differential Equations, Vol. 2004(2004), No. 142, pp. 1-9. Title: Uniqueness of positive solutions for a class of ODE's with Dirichlet boundary conditions Authors: Yulian An (Lanzhou Transportation Univ., China) Ruyun Ma (Northwest Normal Univ., Lanzhou, China) Abstract: We study the uniqueness of positive solutions of the boundary-value problem $\displaylines{ u''+a(t)u'+f(t,u)=0 ,\quad t\in (0,b)\cr u(0)=0,u(b)=0\,, }$$ where $0