A panel of monoclonal antibodies was used in an avidinbiotin immunoperoxidase technique to provide an immunohistologic analysis of the inflammatory infiltrates in the gingiva of osseointegrated implants. A total of 27 gingival and 13 interimplant specimens was obtained from 13 patients. Eighteen of the gingival specimens were clinically healthy, while nine showed overt signs of clinical inflammation (GI = 2 or 3). All specimens showed some degree of inflammation histologically, although the size of the inflammatory infiltrate was much greater in the clinically inflamed specimens. There was no significant difference in the proportion of T (50% to 60%) or B (40% to 50%) lymphocytes in either group. The CD4:CD8 ratio also showed no significant difference: 1.6:1 in the healthy group and 2.0 in the inflamed group. Similar ratios were also found in the infiltrates of the interimplant tissue. The immunohistologic analysis suggests that the gingival lesion associated with these implants is a stable, well-controlled response. Keywords: immunohistology, osseointegrated implants