Wolinella rectahas been associated with adult periodontitis, but its role in the disease remains uncertain. This report clarifies the distribution ofW. rectain periodontally healthy and diseased subjects, and treated patients with recurrent disease. A specific polyclonal rabbit antiserum againstW. rectastrain 372 was used for indirect immunofluorescence localization ofW. rectain dental plaque from untreated and treated patients. Supragingival plaque was collected from 15 periodontally healthy individuals (H), 10 adults with mild gingivitis (G1), 8 with severe gingivitis (G2) and 15 with periodontitis (AP). Subgingival samples from 23 diseased sites (G2 and AP) were examined as well. There was a significant difference (p = 0.000) between the proportions ofW. rectain subgingival (4.4%)vs. supragingival (0.3%) plaque samples from AP. A significant difference (p = 0.000) inW. rectaproportions was also detected between subgingival plaque samples of AP (4.4%)vs. G2 (1.2%). No significant difference in the mean % ofW. rectawas found between supragingival plaque of AP (0.3%) and G2 (0%), and samples of G1 (0.01%) and H (0.1%). In a separate study, 85 adults previously treated for moderate to severe adult periodontitis were monitored over a 12‐month period for evidence of disease recurrence. Recurrent disease was detected at 32 sites in 18 subjects. Of these, 20 sites in 13 subjects were positive forW. recta. With subjects as the experimental unit, a significant increase in the proportions ofW. rectawas found at sites with recurrent disease (3.12%) as compared to stable, paired control sites (0.24%), but only when sites with breakdown and positive forW. rectawere compared with their controls. These results indicate thatW. rectais associated with some, but not all sites with advanced adult periodonlilis. The association ofW. rectawith gingivitis was not statistically significan