The aim of this radiographic investigation was to study procedural errors encounterd in root canal treatment in a Jordanian population as evidenced using periapical radiographs A total of 2380 periapical radiographs including 3178 endodontically treated teeth were assessed in respect of the quality of endodontic treatment. The results indicated that the prevalence of endodontically treated teeth in the maxilla was higher than that in the mandible ( P < 0.001 ), the maxillary central incisors have the highest prevalence of endodontic treatment, and the maxillary second molars have the lowest prevalence of endodontic treatment. In respect of the quality of endodontic treatment, 30.2% of endodontically treated teeth exhibited an ideal length of root canal filling, 23.64% of the evaluated teeth were mummified, 37.45% of the teeth have short root canal fillings, 6.25% were overfilled, 1.35% were with preparations which deviated from the line of the root canal and 1.10% of the evaluated teeth have perforations of the root walls or the floor of the pulp chamber. It is concluded that the Maxillary teeth were found to be endodontically treated more frequently than the mandibular teeth, anterior teeth were found to be endodontically treated more than premolar and molar teeth, maxillary central incisors have the highest prevalence of endodontic treatment whilst the maxillary second molars have the lowest prevalence. The quality of endodontic treatment was disappointing. Therefore, emphasis on continuing education and post graduate courses in endodontics must be a priority in Jordan.