Certain active antileukemic and cytotoxic fractions prepared from Tabernaemontana holstii roots were investigated, resulting in the isolation of the known indole alkaloids conoduramine, conodurine, coronaridine, gabunine, 19-oxocoronaridine, pericyclivine, perivine, and vobasine. Two new alkaloids were assigned the structures 19-oxoconodurine and 19-(2-oxopropyl)conodurine. Both gabunine and 19-(2-oxopropyl)conodurine showed significant inhibitory activity against P-388 cell culture. All of the alkaloids are reported for the first time from T. holstii; conodurine, conoduramine, gabunine, perivine, and pericyclivine are reported for the first time from any Tabernaemontana species.