Background: Soft denture liners could be enhanced by adding antimicrobial agents such as silver nanoparticles (AgNPs) and cinnamon extract; however, their cytotoxicity must be evaluated. Materials and Methods: Four groups were tested: group Ⅰ unloaded soft liner (control), group Ⅱ loaded with AgNPs, group Ⅲ loaded with cinnamon extract and group Ⅳ loaded with AgNPs + cinnamon extract. Cell viability was assessed after 24 and 72 hours using the MTT assay. Results: A significant difference among groups was observed (P = 0.03). The unloaded liner showed a significantly higher viability than the cinnamon group at 24 h and was significantly higher than the mixed group at 72 h. All groups had maintained viability above cytotoxic levels. Conclusion: At the tested concentrations, AgNPs, cinnamon extract and their combination demonstrated acceptable biocompatibility in soft denture liners