This randomized clinical trial evaluated the effect of the frequency of self-performed mechanical plaque control (SPC) on gingival health in subjects with a history of periodontitis. Forty-two subjects participating in a routine periodontal maintenance program were randomized to perform SPC at 12-, 24- or 48-hr intervals. Plaque index (PlI) and gingival index (GI) were evaluated at baseline, and days 15, 30 and 90 of study. Probing depths, clinical attachment levels and bleeding on probing were assessed at baseline, days 30 and 90. Mixed linear models were used for the analysis and comparison of experimental groups. Mean GI at baseline remained unchanged throughout study (90 days) only in the 12-hr group (0.7 ± 0.1 versus 0.8 ± 0.1; p < .05). At the end of study, mean GI was significantly increased in the 48-hr group over that in the 12- and 24-hr groups. When GI = 2 scores were considered, only the 48-hr group failed to maintain gingival health throughout the study (18.8%). SPC performed at a 12- or 24-hr frequency appears sufficient to controlling gingival inflammation whereas this clinical status was not maintained using a 48-hr frequency in subjects with a history of periodontitis subject to a routine periodontal maintenance program (ClinicalTrials.gov: 50208115.9.0000.5346).