Biomolecular computing is an interdisciplinary ?eld that draws together mol- ular biology, chemistry, physics, computer science, and mathematics. DNA n- otechnology and molecular biology are key relevant experimental areas, where knowledge increases with each passing year. The annual international meeting on DNA-based computation has been an exciting forum where scientists of d- ferent backgrounds who share a common interest in biomolecular computing meetanddiscusstheirlatestresults. Thecentralgoalofthisconeren f ceisto bring together experimentalists and theoreticians whose insights can calibrate each other’s approaches. DNA7, The Seventh International Meeting on DNA Based Computers,washeldatTheUniversityofSouthFloridainTampa,FL, USA, June 10–13,2001. The organizerssought to attract the most signi?cant - centresearch,withthehighestimpactonthedevelopmentofthediscipline. The meeting had 93 registered participants from 14 countries around the world. The program committee received 44 abstracts, from which 26 papers were presented at the meeting, and included in this volume. In addition to these papers, the Program Committee chose 9 additional papers from the poster presentations, and their revised versions have been added to this volume. As is now a tradition, four tutorials were presented on the ?rst day of the meeting. The morning started with general tutorials by Erik Winfree (Caltech) andJunghueiChen(UniversityofDelaware),designedtobridgebetweentheir respectiveareasofexpertise,computerscienceandmolecularbiology. Mores- cialized tutorials on encoding DNA sequences and on non-standard DNA motifs and interactions were given in the afternoon by Anne Condon (University of British Columbia) and Nadrian C. Seeman (New York University), respectively.