Electronic Journal of Differential Equations, Vol. 2007(2007), No. 74, pp. 1-10. Title: Inverse spectral problems for nonlinear Sturm-Liouville problems Author: Tetsutaro Shibata (Hiroshima Univ., Higashi-Hiroshima, Japan) Abstract: This paper concerns the nonlinear Sturm-Liouville problem $$ -u''(t) + f(u(t)) = \lambda u(t), \quad u(t) > 0, \quad t \in I := (0, 1), \quad u(0) = u(1) = 0, $$ where $\lambda $ is a positive parameter. We try to determine the nonlinear term $f(u)$ by means of the global behavior of the bifurcation branch of the positive solutions in $\mathbb{R}_+ \times L^2(I)$. Submitted August 1, 2006. Published May 15, 2007. Math Subject Classifications: 34B15. Key Words: Inverse spectral problem; $L^2$-bifurcation diagram; logistic equations.