Electronic Journal of Differential Equations, Vol. 2007(2007), No. 43, pp. 1-5. Title: Positive solutions for a class of singular boundary-value problems Authors: Li Xia (Sun Yat-Sen University, Guangzhou, China) Zhengan Yao (Sun Yat-Sen University, Guangzhou, China) Abstract: Using regularization and the sub-super solutions method, this note shows the existence of positive solutions for singular differential equation subject to four-point boundary conditions. Submitted September 19, 2006. Published March 15, 2007. Math Subject Classifications: 34B10, 34B16, 34B18. Key Words: Upper and lower solution; existence; singular equation.