This review paper reports recent advances in the subject of developmental odontogenic cysts, essentially those of the past decade, starting with reference to the new WHO classification (1). On keratocysts, the latest reported recurrence rates are assessed as are their mode of growth, immunocytochemistry, immunology, genetic studies, and work on specific keratocyst antigens. There is a critical account of the group of lesions which includes the gingival cyst of adults, lateral periodontal cyst, botryoid odontogenic cyst and glandular odontogenic cyst, and their possible relationship to one another. On dentigerous cysts, reference is made to the relationship between them and deciduous teeth, as well as to their immunocytochemistry and immunology. Recent work on the unicystic ameloblastomas, their classification and prognosis, is assessed, as is the calcifying odontogenic cyst and its relationship with solid odontogenic tumours.