Abstract. To select an optimal query evaluation strategy for a path query in an object-oriented database system one has to exploit the available index structures on the path. In a database with a large database schema many alternative strategies have to be considered for the evaluation of a path query by choosing from a large set of available indices, which can make the selection of the optimal strategy expensive. We give an algorithm that finds the optimal strategy for evaluating a path query with time complexity independent of the set of indices available in the database. The algorithm considersallpossibleforwardandbackwardtraversalstrategiesandhastimecomplexity O(n2) in the path length n. Incorporating this algorithm into the query optimization for object-oriented database management systems can improve the response time of the system, by optimizing an equally important and frequent type of queries with high efficiency. Key Words. Object-oriented databases, Index selection, Query op...