The Tudor warship Mary Rose was built in Portsmouth, England, between 1509 and 1511 and served in Henry VIII's navy until she sank on July 19, 1545. Over the many years that followed, the hull and her contents were covered by a deposition of sediments. Within this environment, the hull and objects remained protected from further deterioration. Upon recovery from the protective sediments and re-exposure to aerobic conditions, chemical, physical, and biological degradation ensued. Experiments were undertaken to evaluate the effectiveness of passive conservation methods with the view of controlling the activity of wood decay organisms in hull timbers. Storage in CO2 atmosphere, cold storage, reburial, and gamma irradiation were evaluated for their effectiveness in controlling the bacterial, fungal, and insect activity in Mary Rose archaeological timbers. Of these methods, cold storage was shown to reduce microbial activity, although soft-rot fungi were identified growing on hull timbers. The suitability of reburial within anoxic sediments was assessed. Physicochemical conditions were characterized by a near neutral pH, low Eh, and absence of dissolved oxygen. However, cellulolytic activity in recent and Tudor sediments was demonstrated. Gamma irradiation was found to be a highly effective passive conservation method against bacteria, fungi, and insects. A dose of 15 KGy is required for inactivation of these organisms. At doses in excess of 100 KGy radiolytic damage resulted in increased hygroscopicity, increased cracking and warping, loss of surface texture, reduction in compression and bending strength, and chemical alteration and degradation of cell wall components. This work concluded that cold temperature and gamma irradiation are suitable methods of storing waterlogged archaeological wood for long periods. Following long-term storage of the hull (1982-1994), an active conservation technique involving a two-stage polyethylene glycol treatment method has been employed to retain the structural integrity of the waterlogged hull timbers. Active conservation of the hull commenced in 1994 and will be completed by 2008. controlled air-drying will then dry the hull timbers.