Electronic Journal of Differential Equations, Vol. 2003(2003), No. 57, pp. 1-21. Title: Positive solutions for indefinite inhomogeneous Neumann elliptic problems Authors: Yavdat Il'yasov (Univ. de La Rochelle, France) Thomas Runst (Friedrich-Schiller-Univ., Jena, Germany) Abstract: We consider a class of inhomogeneous Neumann boundary-value problems on a compact Riemannian manifold with boundary where indefinite and critical nonlinearities are included. We introduce a new and, in some sense, more general variational approach to these problems. Using this idea we prove new results on the existence and multiplicity of positive solutions. Submitted January 10, 2003. Published May 19, 2003. Math Subject Classifications: 35J70, 35J65, 47H17. Key Words: p-Laplacian; nonlinear boundary conditions; indefinite and critical nonlinearities.