This volume contains contributions to the 17th International workshop on Graph-Theoretic Concepts in Computer Science (WG '91) held in Southern Bavaria in June 1991. These annual workshops are designed to bring together researchers using graph-theoretic methods to discuss new developments relating to or emerging from a diversity of application fields. The topics covered in this volume include: tree-related problems, graph grammarsand rewriting, complexity, computational geometry, parallel algorithms, vertex orderings, path-oriented algorithms, applications to VLSI, and disjoint cycle problems.