Abstract We describe Macrocentrum aurimontium (Melastomataceae: Merianieae), a new species that has been collected twice in the state of Pará, Northern Brazil. Macrocentrum aurimontium closely resembles M. latifolium, a species from French Guiana, due to its isomorphic leaves and 4-merous flowers, but differs from it by the eglandular trichomes up to 4 mm long on the adaxial foliar surface (vs. glabrous or deciduously strigulose, then the trichomes 0.1–0.2 mm long in M. latifolium), denticulate to denticulate-serrulate, always ciliate leaf margin (vs. minutely serrulate, eciliate), sepals 0.5–0.7 mm long, triangular to broadly triangular, with an obtuse to rounded apex, the external teeth projecting 0.2–0.5 mm above them (vs. sepals ca. 0.1 mm long, oblate, the external teeth with the same size as the sepals) and the fruits shorter and narrower (2.7–3.7 × 1.2–1.4 mm vs. 4–5.5 × 3.1–4 mm).