Tongkat Ali (Eurycoma longifolia) is a small understory treelet found both in primary and secondary forests of Southeast Asia. Traditionally, the root of tongkat ali tree has been harvested from the wild for its many purported medicinal uses. Currently, tongkat ali is grown commercially in plantation to meet the demand of this medicinal plant. However, systematic research is still lacking, especially on the performance of tongkat ali under conventional rubber cultivation. Field Block A, Penawar division, Research station of Kota Tinggi, Johor has been planted with tongkat ali under rubber ecosystem, in a trial that commenced nearly 19 years ago. Girth of 19-year-old rubber trees is 59.9 ± 1.0 cm and circa 80% of the area can still be tapped. For 19-year-old tongkat ali, the average stem girth was 29.7 ± 2.3 cm and the height was 7.0 ± 0.4 m. The average fresh and dry root per tree was 4.3 ± 0.7 kg tree-1 and 3.0 ± 0.43 kg tree-1, respectively. The dry weight of root in this study was higher than most tongkat ali intercropping studies reported in Malaysia. As for the quality of roots, it contained 0.88% of eurycomanone and 22.22% of antioxidant activity. The eurycomanone content is at a satisfactory level when compared to that obtained from the wild and other tongkat ali intercropping plantations. The roots also contained low levels of heavy metals that is 0.96 mg kg-1 of lead, 0.05 mg kg-1 of cadmium, 0.35 mg kg-1 of mercury and 0.41 mg kg-1 of arsenic. The heavy metal content in roots were below the level permissible by the National Pharmaceutical Regulatory Agency (NPRA). Based on the present study, it was concluded that cultivation of tongkat ali under the shade of rubber can optimize land use and provide additional income to rubber growers as well as contribute to the sustainability of the local herbal industry.