Commercial essential oils from 29 plant species were tested for their nematicidal activity against the pine wood nematode, Bursaphelenchus xylophilus. Good nematicidal activity against B. xylophilus was achieved with essential oils of Gaultheria fragrantissima and Zanthoxylum alatum. GC-MS analysis of the corresponding oils led to the identification of two and ten major compounds, respectively. Four compounds, methyl salicylate, ethyl salicylate, methyl trans-cinnamate and ethyl trans-cinnamate, were tested individually for their nematicidal activities against the pine wood nematode. Methyl and ethyl salicylates showed strong nematicidal activity at concentration of 2.0 mg ml–1. Concentrations of 1.0 mg ml–1, as well as lower concentrations showed only minor effects. Another compound, methyl trans-cinnamate, showed 100% activity at concentrations of 0.0625-2.0 mg ml–1. With ethyl trans-cinnamate, 100% mortality was observed at concentrations of 0.25-2.0 mg ml–1. The essential oils and their components described herein merit further study as potential nematicides against the pine wood nematode.