The presence of leukocytes within the crevices of clinically healthy and chronically inflamed gingivae has been studied in human and dog. Cellular samples were obtained from the gingival crevices by the “Styroflex” technique. The area on the styroflex film showing the presence of leukocytes was determined and a differential count of the cells performed. Biopsies were also taken from dogs with clinically healthy gingivae.Neutrophils, lymphocytes and monocytes were regularly found in samples from clinically healthy gingivae even when histological sections failed to show any inflammatory infiltrates in the gingival connective tissue. The differential counts showed 95–97 % neutrophils, 1–2 % lymphocytes and 2–3 % monocytes. Increased numbers of leukocytes were found in the crevices of chronically inflamed gingivae. However, the proportions of the various leukocytes were the same as those found in the crevices of clinically healthy gingivae. The results of the present investigation support the view that only quantitative differences exist between clinically healthy and chronically inflamed