International association dental traumatology has published guideline for the primary dentition. The guideline indicates that, when the crown is dislocated in a labial direction, extraction of the affected tooth is the only choice of treatment for lateral luxation cases with severe displacement. However, retaining primary teeth is important. Here we present a case of a tooth with lateral luxation and severe displacement.A three-year-old girl presented with complaint of severe mobility of the left lower primary canine caused by hitting a water tap 1 month earlier.We performed a root canal filling after pulpectomy and crown height reducing. After 37 weeks, radiographic examination showed dramatically alveolar bone regeneration and we were able to treat and maintain.We conclude that conservative treatment of a traumatized tooth can be effective even in cases of lateral luxation and severe displacement.