Introduction: The aims of this study were to describe the cause, lesion characters and radiography of immature permanent teeth. Materials and Method: From Jan 2012 to June 2013, the authors had treated 38 open apices teeth of 32 patients in Hanoi National Odonto-Stomatology Hospital and Dental Health Care 225 Truong Chinh. Results: The main causes were dens evaginatus (94.12 percent in premolars) and traumas (75 percent in male and 100 percent in incisors). Apical periodontitis was main disease (86.85 percent). On radiography, roots were at stage III in 63.16 percent of the cases and 86.85 percent with periapical lesion. Conclusion: Lesion characters of patients with open apices teeth were very variety and apical periodontitis was quite more common.