Antifungal properties of polyvinylchloride (PVC) and wood/PVC composites (WPVC) were studied with two different fungicides through disk diffusion and dry weight techniques against Aspergillus niger as a testing fungus. Three different types of woods, including Xylia kerrii Craib & Hutch.(XK), Hevea brasiliensis Muell.(HB), and Mangifera indica Linn.(MI), were used. The disk diffusion results revealed that the addition of 3-iodopropinyl-N-butylcarbamate (IPBC) in the PVC and WPVC markedly reduced the diameter of fungi, whereas the addition of methylbenzimidazole-2-ylcarbamate(Carbendazim) did not. The results from IPBC samples by the dry weight technique corresponded to those by the disk diffusion method. Adding fungicides tended to slightly increase the flexural properties of PVC, whereas in the case of WPVC those properties were deteriorated by IPBC and carbendazim additions. The total color change was less when IPBC only was introduced into PVC. FTIR spectra suggested that no chemical structure changes were observed after the addition of IPBC and carbendazim. The higher surface contact angle and fungicide release values for IPBC samples could imply greater diffusibility of IPBC in PVC and WPVC matrices, accompanied by increased antifungal activity. WPVC with HB wood showed the best antifungal performance, at an optimal concentration of 10,000 ppm, when compared with XK and MI woods. POLYM. ENG. SCI., 54:1248–1259, 2014. © 2013 Society of Plastics Engineers