Background. This paper reports a case with end-on-molar relation with maxillary anterior teeth proclination, lower anterior teeth crowding, and deep bite. The case was successfully treated in a short span. Clinically significant improvement in the dimensions of the maxillary and mandibular dental arch forms and sufficient space for the eruption of permanent teeth was observed. Conclusion. Therefore, it can be concluded that preorthodontic trainer is a valid treatment of choice in mixed dentition where transverse expansion is a part of the treatment plan, as the results obtained are within short period of time and have less chances of relapse, because the correction of a malocclusion is by elimination of soft tissue dysfunction.