The paper describes the microscopic characteristics of the leaves of Bauhinia blakeana Dunn., known in Brazil as "pata de vaca" and used as a hypoglycemic remedy. Transverse sections and epidermal dissociations indicate the presence of a dorsiventral mesophyll protected by epidermis with trichomes of diverse types and paracytic and anomocytic stomata. The petiole, which is plane-convex, pubescent, shows two excrescences, an angular collenchyma and collateral and bicollateral vascular bundles.