Myrcia longipetiolata, a new species of Myrcia is here described and illustrated. This species resembles M. unana due to its long leaves, acute or acuminate leaf apex, cuneate leaf base, long petioles, but differs by its larger leaves, lanceolate bracteoles, rounded or apiculate calyx lobes and floral disc of 3 mm diam. Besides, these two species share the area of occurrence (southern Bahia). We also provide the phylogenetic relationships of M. longipetiolata within the genus, morphological comparisons with related species, comments of its distribution, habitat and conservation status.