HYACINTH is the acronym for "Deployment of HYACE tools In new tests on hydrates", a project funded by the European Framework Five programme. The project is being carried out by a consortium of six companies and academic institutions from Germany, The Netherlands and the United Kingdom. The primary objective of the project is to bring the wireline pressure corers developed in the earlier HYACE Project, together with new core handling technology developed in the HYACINTH Project, to the operational stage. The first scientific results obtained with the HYACE/HYACINTH technology were achieved on ODP Leg 204 in the summer of 2002. Hydrate core was recovered from the seabed at in situ pressure, successfully transferred into laboratory chambers without loss of pressure, then geophysically logged. Some of the results of this operation are shown. Further use of the system is planned in the Gulf of Mexico in the spring of 2004. The system of pressure corers and laboratory chambers, which allows pressure cores to be acquired and processed in the laboratory at pressures up to 250 bar, is illustrated. Other developments currently in progress to extend the capabilities of the system are shown: to allow electrical resistivity logging of the pressure cores; to enable pressurized sub-samples to be taken from the cores; to facilitate microbiological experiments on pressurized sub-samples.