Declarative languages have long promised the ability to rapidly create easily maintainable software for complex applications. The International Symposium of Practical Aspects of Declarative Languages (PADL) provides a yearly - rum for presenting results on the principles the implementations and especially the applications of declarative languages. The PADL symposium held January 19-20, 2009 in Savannah, Georgia was the 11th in this series. This year 48 papers were submitted from authors in 17 countries. The P- gram Committee performed outstandingly to ensure that each of these papers submitted to PADL 2009 was thoroughly reviewed by at least three referees in a short period of time. The resulting symposium presented a microcosm of how the current generation of declarative languages are being used to address real applications, along with on-going work on the languages themselves. The program also included two invited talks, Inspecting and Preferring Abductive Models by Luis Moniz Pereira and Applying Declarative Languages to C- mercial Hardware Design by Je? Lewis. Regular papers presented a variety of applications, including distributed applications over networks, network veri?- tion, user interfaces, visualization in astrophysics, nucleotide sequence analysis and planning under incomplete information. PADL 2009 also included ongoing work on the declarative languages themselves. Multi-threaded and concurrent Prolog implementation was addressed in several papers, as were innovations for tabling in Prolog and functional arraysin Haskell. Recent applications have also sparked papers on meta-predicates in Prolog and a module system for ACL2.