Abstract This study evaluated the cytotoxicity of Sealapex Xpress and Real Seal XT and their effect on macrophage activation. J774.1 macrophages were incubated with Sealapex Xpress and Seal Real XT (0.1, 1.0, and 10 mg/mL) for 24 and 48 h. Cell viability was assessed by the MTT assay and macrophage activation was measured by pro- and anti-inflammatory cytokine production using ELISA. Data were analyzed using one-way ANOVA and Tukey’s post-test (a=0.05). Cell viability was not affected with 0.1 or 1.0 mg/mL of extracts of Sealapex Xpress and Real Seal XT at 24 and 48 h (p>0.05), but was significantly lower when cells were exposed to 10 mg/mL of both sealers (p<0.05). Sealapex Xpress inhibited the production of TNF-a, whereas Real Seal XT induced TNF-a secretion at 24 h (p<0.05). IL-6 production was induced by Real Seal XT, but not by Sealapex Xpress (p<0.05). Real Seal XT and Sealapex Xpress induced the secretion of anti-inflammatory IL-10. IL-4 was not detected in any group. In conclusion, both sealers had low toxicity but differentially activated macrophages. Macrophage activation by Sealapex Xpress was characterized by inhibition of TNF-a and induction of IL-10, whereas Real Seal XT induced IL-6 solely.