The effectiveness of the preparation with borax, boric acid and copper sulphate salt (BBC) as a water borne wood preservative was studied in the laboratory soil-block test. Blocks of civit (Swintonia floribunda) and chapalish (Artocarpus chaplasha) wood were dip-treated with the preservative solution and exposed to a common white rot fungus (Polyporous versicolor) and a brown rot fungus (Poria nionticola). The loss in weight of the wood blocks due to the fungal decay was recorded to be in the range 0-1.4%. This showed that the preservative was very effective. The field test of the preservative is being carried out with chapalish and garjan (Dipterocarpus spp.) wood stakes along with untreated ones. All the untreated stakes deteriorated due to fungi or other wood destroying agents within two years, but the treated stakes remained uneffected even after five years of exposure.