A qualitative and quantitative histological study of the initial healing response adjacent to 24 submerged and non-submerged implants placed in the lower jaws of 6 monkeys is presented. The histomorphometric analysis showed no significant differences in mineralized bone-implant contact length between submerged and non-loaded non-submerged titanium implants. The infrabony defects around some of the implants on the radiographs were significantly correlated to the histological measurements. Qualitatively, a greater number of gingival inflammation cells and a longer junctional epithelium were seen adjacent to non-submerged implants without oral hygiene than were seen adjacent to non-submerged implants with oral hygiene in the initial healing period.