Two fumigants (methyl bromide and sulphuryl fluoride) were used to treat freshly sawn radiata pine (Pinus radiata D. Don) lumber and log sections to evaluate their influence on development of kiln brown stain. Both treatments reduced severity of stain when compared with controls. The sulphuryl fluoride treatment was notably better than methyl bromide at the highest fumigant dosage, but levels of overall stain were still considered unacceptable with only 20–30% of lumber having either no or slight stain beneath the surface. Sulphuryl fluoride showed superior penetration into sapwood compared to methyl bromide as determined by a colour assay of parenchyma cell viability. A fungicide formulation which was successful in preventing brown stain in kiln dried eastern white pine was ineffective against kiln brown stain in radiata pine. The results of the present study indicates that the mechanism for kiln brown stain in radiata pine differs from that in eastern white pine.