  This volume contains selected papers presented at the 9th International
Workshop on Reduction Strategies in Rewriting and Programming, WRS2009, which
was held in Brasilia on the 28th June 2009, associated to RTA 2009 (the 20th
International Conference on Rewriting Techniques and Applications) at RDP, the
Federated Conference on Rewriting, Deduction and Programming. Reduction
strategies define which (sub)expression(s) should be selected for evaluation
and which rule(s) should be applied. These choices affect fundamental
properties of reductions, such as completeness, laziness and efficiency in
general. The WRS workshops promote research and collaboration in the area of
reduction strategies and their applications in specification and programming,
theorem proving, software engineering, etc.
