This proceedings volume presents the talks from the Fifth Annual Meeting on DNA Based Computers held at MIT. The conference brought together researchers and theorists from many disciplines who shared research results in biomolecular computation. Two styles of DNA computing were explored at the conference: DNA computing based on combinatorial search, where randomly created DNA strands are used to encode potential solutions to a problem, and constraints induced by the problem are used to identify DNA strands that are solution witnesses; and DNA computing based on finite-state machines, where the state of a computation is encoded in DNA, which controls the biochemical steps that advance the DNA-based machine from state to state. Featured articles include discussions on the formula satisfiability problem, self-assembly and nanomachines, simulation and design of molecular systems, and new theoretical approaches.