Mandibular infected buccal cysts occur on the buccal and distal aspects of the roots of partly or fully erupted mandibular molars with vital pulps. In the present investigation six cases associated with mandibular first and second molars were studied. The cysts were lined with a non-keratinised squamous epithelium with a mixed inflammatory cell infiltrate in the connective tissue. The clinical and microscopic features were similar to those of previously reported paradental cysts. The inflammation always present in these cysts may have an important role in their pathogenesis. It may induce periodontal pocketing, which may lead to hyperplasia and cyst formation in adjacent odontogenic epithelium, which may be either remnants of the reduced enamel epithelium or cell rests of Malassez.