In Thailand, many buildings were adorned with murals. Many of these wall paintings have now been totally destroyed by climate, vandalism and neglect; a few still remain. The conservation of wall paintings has two important parts: (i) consolidation of the building or structural conservation, and (ii) conservation of the paintings. The Thai wall paintings were usually done in the tempera technique. This article discusses problems of conservation due to climate and decay of materials, rain water, capillary water and biological growth. A problem prevalent in almost all wall paintings is the flaking of the paint from the plaster. A solution of soluble nylon was used to consolidate the paint; this has worked very satisfactorily. Some specific monuments are described which were treated or are in need of treatment. The author suggests treatment methods. See also <i>AATA 12-48. -- AATA