Durability of 12 species of Creosote Fuel Oil (CFO) treated timbers (Bombax ceiba, Mimusops sp Acrocarpus fraxinifolius, Chnukrasia velutina, Abies pindrow, Callophyllum apotalum, Pterocarpus marsupium, Mesua ferrea, hopea parviflora, Terminalia alata, Anogeissus latifolia  and Lagerstroemia microcarpa) in Cochin Harbour is discussed in detail. Compared with the natural durability all the treated panels demonstrated excellent life. After 17 years of exposure tests also as many as six species are continuing in the field. Non-durable timbers viz B.ceiba, A.fraxinifolius, C.velutina, Mimusops sp. and A. pindrow  accomplished equal or superior durability like such durable species as C.apotalum, P.marsupium, M. ferrea, H.parviflora, A.latifolia and L. microcarpa after CFO treatment. A single species selected from different geographical localities exhibited no consistency in its performance either in untreated or treated condition. Results of similar tests conducted at other harbours of the country when compared with the present ones revealed that the performance of a species after preservative treatment also may vary from one harbour to the other.