This book constitutes the refereed proceedings of the International RuleML Symposium on Rule Interchange and Applications, RuleML 2010, held in Washington, DC, USA, in October 2010 - collocated with the 13th International Business Rules Forum Conference 2010. The 14 revised full papers and 7 revised short papers presented together with the abstracts of 3 keynote lectures were carefully reviewed and selected from 42 submissions. The accepted papers address a wide range of rule topics, including traditional topics, such as rules and uncertainty, rule-based event processing and reaction rules, rules and inferencing, rule transformation and extraction, rules, semantic technology, and cross-industry standards, rules and norms, rule-based distributed/multi-agent systems, and miscellaneous rule topics.