Three methods for treatment of periodontal pockets (subgingival curettage, modified Widman flap surgery, and pocket elimination) were applied as a clinical trial to 82 patients. Follow up results over one to five years after the initial treatment are reported. The variations in attachment levels and pocket depth were analyzed statistically as related to methods of treatment and yearly time intervals following the initial treatment. The most favorable results regarding gain or maintenance of attachment levels and reduction of pocket depth were observed interproximally. Subgingival curettage provided the greatest gain in attachment level up to three years postoperatively, but after four to five years there was no significant difference in results following the three methods. The most significant loss of attachment and return of pocket depth occurred on the buccal aspects of the teeth, and the results were not significantly different for the three methods except at the first year of follow up when the attachment level was maintained best after curettage.