Topics of interest for APPROX and RANDOM are: design and analysis of approximation algorithms, hardness of approximation, small space algorithms, sub-linear time algorithms, streaming algorithms, embeddings and metric space methods,mathematicalprogrammingmethods,combinatorialproblemsingraphs andnetworks,gametheory,markets,andeconomicapplications,geometricpr- lems, packing, covering, scheduling, approximate learning, design and analysis of online algorithms, randomized complexity theory, pseudorandomness and - randomization,randomcombinatorialstructures, randomwalks/Markovchains, expander graphs and randomness extractors, probabilistic proof systems, err- correctingcodes,average-caseanalysis,propertytesting,computationallearning theory, and other applications of approximation and randomness. The volume contains 25 contributed papers, selected by the APPROX Program Committee out of 56 submissions, and 28 contributed papers, selected by the RANDOM Program Committee out of 57 submissions.