Electronic Journal of Differential Equations, Vol. 2012 (2012), No. 136, pp. 1-11. Title: Boundary behavior of large solutions for semilinear elliptic equations in borderline cases Author: Zhijun Zhang (Yantai Univ., Shandong, China) Abstract: In this article, we analyze the boundary behavior of solutions to the boundary blow-up elliptic problem $$ \Delta u =b(x)f(u), \quad u\geq 0,\; x\in\Omega,\; u|_{\partial \Omega}=\infty, $$ where $\Omega$ is a bounded domain with smooth boundary in $\mathbb{R}^N$, $f(u)$ grows slower than any $u^p$ ($p > 1$) at infinity, and $b \in C^{\alpha}(\bar{\Omega})$ which is non-negative in \Omega and positive near $\partial\Omega$, may be vanishing on the boundary. Submitted June 30, 2012. Published August 19, 2012. Math Subject Classifications: 35J55, 35J60, 35J65. Key Words: Semilinear elliptic equations; boundary blow-up; boundary behavior; borderline cases.