The Author presents three cases of tooth germ transplantation which were periodically checked by x-rays to show the progressive root development. The clinical result obtained were quite satisfactory. The situations requiring the transplantations in the 3 cases were all rather unusual: in one case the tooth germ was inside a large follicular cyst; in the other two the tooth germs were mesiodistally rotated 90 degrees which made eruption impossible. The cases described differ from cases frequently found in literature in that the transplanted tooth germs were in the initial stage of development; the roots, in fact, had not yet begun to develop. All the tooth germs transplanted, once their growth was completed, presented two types of morphological alternations. A reduction in the volume of the pulpar chamber and a pad of radiopaque tissue around the neck of the tooth. We have attempted to give an explanation for both of these alterations. The cases as well as the surgical procedures are described in detail.