Twenty-six tropane alkaloids were identified from the root-bark of Erythroxylum monogynum by GC and GC-MS and twenty of these alkaloids had not previously been reported as constituents of the root-bark. 3α-(3′,4′,5′-Trimethoxybenzoyloxy) tropane was the main base and in addition, three new alkaloids were identified as 3α-isobutyryloxynortropane, 3α-(4-methylvaleroyloxy)tropane and tentatively, 3β-phenylacetoxytropane.