The 2004 European Society of Gene Therapy (ESGT) meeting took place at Tampere Hall in Finland and highlighted advances in a variety of topics, including cancer, zinc-fingers, stem cells, small interfering RNA (siRNA), microRNA, and recent developments of non-viral and viral vectors. This meeting was attended by 513 participants from 32 countries, and included 106 oral and 224 poster presentations. One of the aims of this meeting was to take a critical look at gene therapy and the prospects for the future. Se-veral presentations reported on RNA-based technologies, such as siRNA, as potential new classes of therapeutics against a wide range of diseases and for use in expression libraries to identify functional genes involved in biological phenotypes. Critical assessments were made of other aspects of gene therapy, such as genome editing and the use of protein transduction domains (PTDs) in gene- and protein-based therapies, where many researchers have failed to reproduce initial findings reported in the literature. Safety issues related to viral vectors were also important areas of discussion, especially following details released by the UK Gene Therapy Advisory Committee of perhaps the first known case of lentiviral vector-associated oncogenesis. Finally, updates were presented on the clinical development of viral vectors in anticancer therapies with evidence of significant improvements in the mean survival of patients.