The binderless boards were prepared from steam-exploded pulps of oil palm (Elaeis guineensis Jacq.) fronds and characterised for the mechanical strengths and chemical natures to discuss self-binding. The mechanical strength satisfied the requirements of the relevant standard specifications. To discuss the self-bonding of these binderless boards, lignins isolated by Bjorkman's procedure from oil palm fronds and steam exploded pulps, were analysed by wet chemistry and PY-GC/MS. Lignin of oil palm frond was characterised by esterified p-hydroxybenzoic acid. Some extents of these ester bonds and beta-O-4 linkages of lignin were cleaved during steam explosion, in addition to great condensation of guaiacyl nuclei, as revealed by H-1- and C-13-NMR spectra. Wall polysaccharides of oil palm frond are composed of high concentration of arabinoxylan, which produced furfural during steam explosion. It is suggested that released lignin and furfural derivatives contribute to self-binding of the steam exploded pulps.