Enamel matrix proteins, including Emdogain, have been proposed as a new modality for regenerative periodontal treatment. However, limited information is available concerning the clinical applicability and therapeutic results with Emdogain. The aim of the present study was therefore to evaluate the clinical outcome following the application of Emdogain in the treatment of intrabony periodontal defects. Twenty-eight patients with marginal periodontitis (thirty-two 2- and 3-walled intrabony defects) were included in this study. The following parameters were evaluated prior to treatment and 8 months after treatment: probing pocket depth, recession of the gingival margin, and clinical attachment level. The postoperative healing phase was uneventful in all cases. There were no complications such as allergic reactions, abscess formation, or infections throughout the entire study period. The mean probing pocket depth was reduced from 8.7 ± 1.5 mm at baseline to 4.3 ± 1.6 mm after 8 months (P 0.001), the mean gingival recession increased from 1.8 ± 1.2 mm to 3.3 ± 0.9 mm, and the mean clinical attachment level changed from 10.6 ± 1.9 mm to 7.6 ± 1.8 mm (P 0.001). New hard tissue formation was radiographically observed in 26 of the 32 defects. The present results suggest that the treatment of intrabony periodontal defects with Emdogain may lead to significant improvements of all of the investigated clinical parameters. However, controlled histologic and clinical trials are needed to compare this treatment modality with other conventional and regenerative periodontal surgical methods.