Impaction of mandibular second permanent molars is a rare occurrence, with prevalence rates reported to be between 0.65% and 2.0%. In the absence of systemic conditions, impactions are usually unilateral. There appears to be no consensus as to the optimal treatment for impacted mandibular second molars and treatment plans will be based upon the individual case. Treatment may involve orthodontics and/or various surgical techniques, and early diagnosis is important. This paper presents an unusual case of bilateral transverse impaction of both mandibular second and third molars that was diagnosed at 18 years of age. All impacted molars were extracted.