Dentin dysplasia, type II, is an inherited autosomal dominant disorder in which primary teeth are amber and translucent, with pulp chambers obliterated by abnormal dentin. The permanent teeth have a normal coronal morphologic character and coloration but exhibit “thistle tube”–shaped pulp chambers as well as numerous pulpal calcifications. The disorder has traditionally been thought to be somewhat rare; however, this article presents 2 new families in which several generations with the disorder were reported to the authors within a 1-year period. It also includes a review of the literature documenting a total of 17 previously reported families. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1999;87:752-5)