Various physical characteristics of a new glass ionomer root canal sealer were tested. These included setting time, ease of delivery to the root canal, adaptability and adhesion to the dentinal wall of the root canal, and radiopacity. Scanning electron micrographs and electron microprobe analyses were made. The characteristics were compared with those of Grossman's sealer. The results indicated that, with respect to the properties tested, the glass ionomer sealer was superior to Grossman's sealer.