Root-knot nematode Meloidogyne incognita is a soil-borne pathogen in plantation crops. Tea, coffee, pepper, tobacco, and patchouli plant have been reported as host of this nematode. Environmentally friendly, inexpensive, and effective technique is required to control the population of M. incognita. Utilization of tithonia plant as botanical nematicide is an alternative solution needs to be applied. A total of 1:10 (w/v) of leaves, stems, and flowers of tithonia was boiled. Further, the decoction was used in the in vitro mortality test of J2 of M. incognita. The result showed that decoction of leaves, stems, and flowers of tithonia at various concentrations led to nematicidal effect against M. incognita. Best performance of nematicidal activity was found in the decoction of flowers at a concentration of 50%. This study provides new information concerning nematicidal effect of decoction of leaves, stems, and flowers of tithonia against M. incognita.