The solutions of five organotin compounds, i.e., TBTA, TBTC, TBTO, TBTP and TBTAL, are prepared in methanol, and in three concentrations of 0.5%, 1.0% and 1.5%. The organotin/methanol solutions are used to treat wood samples of two species, i.e., Cunnighamia lanceolata (Lamb.) Hook, and Cryptomeria japonica D. Don. The decay resistances of treated samples are investigated and compared to the CCA (4%) treated samples. It is shown that organotin compounds are comparable to wood preservatives CCA. Besides, the preservative properties of organotin compounds, (C_4 H_9 ) SnX, do not change singificantly with different X groups.