The Sixth International Conference on Systems Biology (ICSB 2005) will be held from October 19th to 22nd, 2005, at Harvard Medical School's new conference center, in Boston. It will bring together scientists from all over the world with expertise in experimental, theoretical and computational approaches to understanding biological systems at many levels. We expect the 550 attendees to range from graduate students (or even undergraduates) to established researchers, and to include scientists from academia, industry and government laboratories. [unreadable] [unreadable] The conference program comprises six sessions, provisionally titled: Intracellular dynamics; Biology by design (synthetic biology); Intracellular networks (signal transduction and transcriptional regulation); Multicellular networks (development and pattern formation); Mechanics and scale in cellular behavior; and Evolution in action (including experimental evolution). Our goal is to promote effective communication and collaboration among the different disciplines and approaches that are needed to make progress in identifying the general principles that underlie the structure, behavior, and evolution of cells and organisms. [unreadable] [unreadable] We will have at least 24 invited speakers, two poster sessions, and up to five contributed talks. The speakers and contributors will include experimental biologists, chemists, computer scientists, physicists, engineers, and mathematicians. [unreadable] [unreadable]