The role of personal plaque control in periodontal maintenance care was studied in 78 patients who had undergone periodontal therapy and were on 3-month recall for prophylaxis over 8 years. Variations in pocket depth and attachment levels were related to individuals with plaque scores above and below the median. The results also were analyzed by comparing the 25% of the sample having the lowest plaque scores with the 25% having the highest scores over 7 years of maintenance care. Students t test was used. It was found that personal oral hygiene as expressed in plaque scores was not critical for maintenance of post-treatment pocket depth and attachment levels in patients with professional tooth cleaning every 3 months. The initial post-treatment reductions in pocket depth and variations in attachment levels were more favorable in patients with good than with poor oral hygiene, but, these differences were not significant after 3 to 4 years of maintenance care.