This is the first report of basal root rot of teak, caused by Phellinus noxius, in Peninsular Malaysia. The disease aggressively killed its host irrespective of health status. Bark depression at the root collar was a very characteristic symptom of this disease on teak and was visible from a distance. Below ground, infected trees had rotted root systems, mainly at the collar region, brown discoloured wood and irregular golden-brown honeycomb-like pockets of fungal hyphae in the roots. Pathogenicity tests showed that the fungus killed 2-year-old teak saplings gradually, producing below- and above ground-symptoms similar to those in the plantation. The disease killed all the infected hosts within 3 months, irrespective of wounded or unwounded treatments.