The International Workshop on Algorithms and Computation is intended to provide an international forum for researchers working in the areas of algorithms and computation. The first workshop (WALCOM 2007) was organized in 2007 at Dhaka, Bangladesh, and since then, it is held annually with its venue alternating every year between India and Bangladesh. WALCOM 2013 will be organized by Department of Computer Science and Engineering, Indian Institute of Technology (IIT), Kharagpur, India, and the workshop sessions will be held at Gargi / Moitreyee Auditorium of Ramanujan Complex of IIT Kharagpur, India. The range of topics within the scope of WALCOM 2013 includes (but is not limited to): Approximation Algorithms, Combinatorial Algorithms, Combinatorial Optimization, Computational Biology, Computational Complexity, Computational Geometry, Data Structures, Discrete Geometry, Experimental Algorithm Methodologies, Graph Algorithms, Graph Drawing, Parallel and Distributed Algorithms, Parameterized Complexity, Network Optimization, Online Algorithms, Randomized Algorithms, String Algorithms. The proceedings of accepted papers will be published in the Lecture Notes in Computer Science by Springer-Verlag. A special issue on WALCOM 2013 will be published in Journal of Graph Algorithms and Applications.