Resumo. Sandflies are important vectors of tegumentary and visceral leishmaniasis in different countries. This study aimed at analyzing the histomorphological characteristics of digestive and reproductive organs in Lutzomyia wellcomei (Fraiha, Shaw & Lainson) using light microscopy techniques. Thirty females from the rural area of Nísia Floresta, Rio Grande do Norte state were selected, microsectioned and analyzed with an optical microscope using conventional hematoxylin-eosin staining. Results show three well-characterized regions in the digestive tube: the stomodeum, mesentery and proctodeum. The stomodeum is lined internally with a basal and epithelial membrane; the mesentery has a peritrophic matrix formed above the stomodeum lining consisting of the simple cubic epithelium overlapping the conjunctive, also common to a capsule of gonadal lining; and the proctodeum, which structurally resembles the mesentery, but with a pyloric sphincter limiting the posterior midgut. Enveloping the digestive tube is the peritoneal membrane, of mesodermal origin. Richly-detailed internal morphological characteristics of L. wellcomei have widened knowledge of this Leishmania braziliensis (Vianna)-transmitting species, an etiologic agent of American tegumentary leishmaniasis.