The aim of the present study was to evaluate the effect of resilient denture liner in implant tissue-supported mandibular overdentures on the masticatory muscles activity of completely edentulous patients.Methods: Twelve completely edentulous male patients were randomly selected and equally divided into two groups. Both groups were rehabilitated two implant tissue-supported mandibular overdentures. However, Group (I) Patients had received two-implant and tissue-supported mandibular overdentures without resilient denture lining material and Group (II) Patients had received two-implant and tissue-supported mandibular overdentures lined with resilient denture lining material. For all patients the Masseter and Temporalis muscle activities were evaluated using surface Electromyography (sEMG).Results: The results revealed that the Masticatory muscle activity had decreased by application of resilient denture liners to the mandibular overdentures in Group (II) patients.Conclusions: The resilient denture liners used with two-implant overdentures may decrease the masticatory muscle activity providing better masticatory efficiency and patient comfort with less effort of masticatory muscles.