Vietnam is a hot spot for biodiversity with more than 10,000 plant species of which 4000 - 5000 are used for medicinal purposes. Studies on endophytic actinomycetes have recently been done in several countries and it can be seen that they are highly diverse and there is a potential for numerous medicinal applications. In this study, fifty two isolates of endophytic actinomycetes were found on three different species of mangrove tree in Nam Dinh province, Vietnam. Most of the isolates (28/52) inhibited R. sativus root elongation while 38 strains were antagonistic towards A. niger and 40 strains were antagonistic towards C. albicans. The two strains, 2E20 and 2E29, showed both antifungal and root growth inhibition activities (75 and 79 percent respectively) and were chosen to be used for tests on cancer cell lines. Crude ethanol extracts of the 2E20 and 2E29 culture both showed anticancer activities at a concentration of 128 ug/mL on four different cancer cell lines, that of KB, SK-LU-l, HepG2 and MCF7 (13, 10, 13 and 34 percent and 10, 12, 5 and 48 percent, respectively). The two species have a high potencial for additional applications and further studies on the two strains are warranted.