The papers contained in this volume were presented at the 4th Annual Symposium on Combinatorial Pattern Matching, held in Padova, Italy, in June 1993. Combinatorial pattern matching addresses issues of searching and matching of strings and more complicated patterns such as trees, regular expressions and extended expressions. The goal is to derive non-trivial combinatorial properties for such structures and then to exploit these properties in order to achieve superior performance for the corresponding computational problems. The area is expected to grow further due to the increasing demand for speed and efficiency that comes especially from molecular biology and the Genome Project, but also from such diverse areas as information retrieval, pattern recognition, compilers, data compression and program analysis.