The objective of this study is to evaluate the anti-cancer and anti-inflammatory activities of plum (Formosa, Oishiwase, Soldam) for the future development of functional food products. To determine the anti-inflammatory effect of different types of plums, the inhibitory effect of plum extracts on nitric oxide (NO) production were measured in lipopolysaccharide (LPS)-stimulated Raw 264.7 mouse macrophage cells and human cancer cell lines (A549, Ags, Hela, Hep3B). Among the three different plum cultivars, Oishiwase at a concentration of 1 mg/mL showed the highest inhibitory effects on NO production (%) in Raw 264.7 macrophage cells. Moreover, Oishiwase exhibited a higher anti-cancer activity against A549 (renal carcinoma, 50%), Ags (gastric carcinoma, 35%), HeLa (cervical carcinoma, 50%), and Hep3B (hepatocellular carcinoma, 31%) at a concentration on 1 mg/mL, respectively, compared to Formosa and Soldam. Our findings suggest Oishiwase plum extracts may serve as potential dietary sources of natural health promoting substances.