Purpose: The purpose of the present study was (1) to assess the relationship between clinical parameters and concentrations of the proinflammatory cytokine IL-6 and the anti-inflammatory cytokine IL-10 in the saliva of totally edentulous patients with implant-supported overdentures; (2) to assess whether estimation of IL-6 and IL-10 levels in saliva could be a useful laboratory tool to detect changes preceding serious clinical complications. Materials and Methods: Thirty healthy adult volunteers (14 men and 16 women) with implant-supported overdentures were recruited from Tallinn Dental Clinic. The biochemical and clinical parameters evaluated were the levels of IL-6 and IL-10 in saliva, pocket probing depth (mm), Gingival Index (0,1, 2, or 3), and bleeding on probing (0 or 1). Results: The level of IL-6 in saliva in the peri-implant disease group was significantly elevated compared to the healthy group. IL-10 could be detected only in the saliva of patients with peri-implant disease, and it did not appear at detectable amounts in saliva of healthy controls. In addition, the levels of IL-6 and IL-10 in peri-implant disease group were positively correlated with clinical parameters. Conclusions: These data suggest that a significant relationship exists between the amount of a proinflammatory cytokine (IL-6) and the inflammatory response in peri-implant tissue. The results also suggest that IL-6 and IL-10 could be used as markers of peri-implant disease together and that the level of the latter cytokine gives additional information about the potency of an organism's integrated immune response for maintenance of inflammatory balance. (More than 50 references) Keywords: dental implants, interleukin-6, interleukin-10, peri-implant disease, peri-implantitis, saliva