The plenary session of the Proteomics Standards Initiative of the Human Proteome Organisation provided an opportunity to update delegates on the progress of the work of the Human Proteome Organisation's Proteomics Standards Initiative (HUPO-PSI) to develop and implement standards in the field of proteomics. Significant advances have been made since the previous congress, with several of the interchange standards and minimal requirements documents being submitted for publication in the literature and being more widely adopted by both manufacturers and data repositories. An exciting development over the interim twelve months is the ongoing merger of the two existing mass spectrometry standards, the PSI mzData and Institute for Systems Biology mzXML, into a single product. This should be achieved by early in 2007.