The fine structures of the surface of Brugia malayi obtained from Mastomys natalensis are demonstrated by scanning electron microscopy. The head of the parasite is bulbous in shape. The amphidial openings lie beside small elevations. The surface structure of the inner papillae is smooth with a small elevation in the middle. The outer papillae are grooved. the cuticular annulation in the midbody region of the female worm is narrower than that of the male cuticle. In the posterior region of the female worm there are tubercles and in one worm a lateral papilla was found near the anus. In both sexes the inconspicuous phasmidial openings are situated in a lateral position close to the caudal tip. In the posterior region of the male worm there is an area with tubercles, the area rugosa and numerous perianal and caudal papillae, which vary in their number and distribution. The surface structures are very similar to those of Brugia pahangi.