This book constitutes the thoroughly refereed post-conference proceedings of the 15th International Meeting on DNA Computing, DNA15, held in Fayetteville, AR, USA, in June 2009. The 16 revised full papers presented were carefully selected during two rounds of reviewing and improvement from 38 submissions. The papers feature current interdisciplinary research in molecular-scale manipulation of matter - in particular, implementation of nanoscale computation and programmed assembly of materials are of interest, thus reflecting a broader scope beyond DNA-based nanotechnology and computation.