Abstract: The present invention relates to a process for treating wood and other cellulosic materials to render the resistance to wood attacking organisms, such as termite, fungi and insects. More particularly, the present invention relates to a process for treating wood with borate preservatives which contain at least one boron-containing component and at least one organic component capable of retaining impregnated borate inside the treated wood even upon contact with water. The organic borate-retaining components are lignin-based materials, alcohol-based materials, protein, and wood extracts.