Wooden shipwrecks in the marine environment form a large part of the underwater cultural heritage. Over the past 50years several wrecks have been excavated, raised and conserved. In the recent past there has been a trend towards preserving these sites in situ, on the seabed, as opposed to raising them. This article gives a brief overview of the deterioration of wood in the marine environment and the principles of the most commonly used methods for conserving waterlogged archaeological wood. Furthermore, a general approach to tackling the in situ preservation of wooden wrecks sites is given.