We investigate the following fourth-order four-point nonhomogeneous Sturm-Liouville boundary value problem:−λ 4 , where 0 ≤ ξ 1 < ξ 2 ≤ 1 and λ i i 1, 2, 3, 4 are nonnegative parameters. Some sufficient conditions are given for the existence and uniqueness of a positive solution. The dependence of the solution on the parameters λ i i 1, 2, 3, 4 is also studied.