Wood samples were taken from pine tree plantations in different regions of Malaysia and investigated for the occurrence of Bursaphelenchus species. Among 13 samples collected from damaged or dead pines in West Malaysia (near Kuala Lumpur) and Sabah (Kinabalu National Park and Sepilok), only one sample of a dead Pinus caribaea tree with bark beetle attack from a plantation near Kuala Lumpur revealed the presence of a new species of Bursaphelenchus. Bursaphelenchus rainulfi sp. n. is characterised by a relatively small stylet lacking distinct basal knobs but with slight basal swellings, lateral field with two lines, female with a small vulval flap, postuterine branch occupying about 33-50% of vulva-anus distance, female tail slim, conoid, with a finely rounded, ventrally bent terminus, male spicules relatively small with high condylus, distinct rostrum but no cucullus, and a small terminal 'bursa' on the male tail. It is similar to B. hellenicus, B. hylobianum and B.abietinus in the shape of the spicules and the female tail as well as in the presence of only two lines in the lateral field. It is distinguished by a number of characters including spicule size, shape of the 'bursa', female tail shape and excretory pore position. Bursaphelenchus rainulfi sp. n. is further distinguished from these morphologically similar species by molecular studies using the ITS-RFLP technique.