Floristic inventories were carried out from February to April 2008 to know the current state of the floristic composition and vegetation structure of the neotropical montane forest of Lanchurán (4°38'S, 79°42'W), province of Ayabaca, Piura Region, Peru. The method proposed by Gentry to study woody plants was followed in two localities that were selected because of their physiographic and floristic characteristics, Los Molinos and La Antena (0.5 ha total). In both localities the soil analysis showed low levels of organic matter, nitrogen, and potassium, and medium levels of available phosphorus. In Los Molinos, a total of 399 individuals/0.25 ha with ≥ 2.5 cm diameter at breast height were found (41 species in 33 genera and 25 families). Additionally, a herbaceous vegetation consisting of 82 species (75 genera and 48 families) was recorded. In La Antena, a total of 86 species in 67 genera and 41 families were found. The plant families with high ecological value, which are also common in others montane forest of the northern and northwestern Peru, are the followings: Asteraceae, Lauraceae, Melastomataceae, Rubiaceae, and Solanaceae. In Los Molinos the basal area was 89.2 m 2, with Lauraceae having the highest values in relative cover, Importance Value Index and Importance Family Value (38.9, 73.1, and 70.8, respectively). The anthropic action stood out as an influencing factor over the floristic diversity found in both sites studied.