Two new triterpenoids, tomentoids A and B (1 and 2), along with five known ones were isolated from the roots of Rhodomyrtus tomentosa. Their structures were elucidated via extensive spectroscopic methods including HR-ESI-MS, UV, IR, and NMR. In addition, compounds 1 and 3-7 exhibited potent inhibitory effects on three tumor cell lines: BGC823, SGC7901, and SK-MEL-110.