From stems and leaves of Humiria balsamifera St. (Aubl.) Hill (Humiriaceae) were isolated 6 triterpenes [arjunolic acid, 2b,3a-dihydroxy-D:A-friedooleanane, friedelin, a-and bamyrins and lupeol], a flavonol (quercetin), an isocoumarin (bergenin) a diterpene (phytol), and 2 phytosteroids (sitosterol and stigmasterol)]. Three sesquiterpenoids [caryophyllene oxide (0.9%), humulene epoxide II (0.3%) and trans-isolongifolenone (0.6%)], a diterpene [phytol (29.4%)] and four aliphatic esters [methyl tetra-(0.3%), hexa-(26.6%) and octadecanoate (0.3%), and ethyl tetradecanoate (26.9%)] were identified by GC/MS. Some crude extracts, arjunolic acid and bergenin, were screened in vivo and/or in vitro for their antimalarial activities against a chloroquine resistant strain. Structures of all isolated compounds were elucidated by spectroscopic analysis, including 2D NMR experiments. All isolates, with the exception of the isocoumarin bergenin, and identified compounds as well as antimalarial activities, are described for the first time for this species.