Electronic Journal of Differential Equations, Vol. 2008(2008), No. 41, pp. 1-7. Title: Existence of positive solution for semipositone second-order three-point boundary-value problem Authors: Jian-Ping Sun (Lanzhou Univ. Technology,Gansu, China) Jia Wei (Lanzhou Univ. Technology,Gansu, China) Abstract: In this paper, we establish the existence of positive solution for the semipositone second-order three-point boundary value problem $u''(t)+\lambda f(t,u(t))=0$, $0