In an animal model, the effect of transferring mature pericranial tissues to immature animals with cranial bone defects was tested. Isogeneic guinea pigs of different ages were used: "infants" (3-4 weeks) and "adults" (> 18 months). Bilateral parietal cranial defects were made in infant guinea pigs and the guinea pigs were divided into three groups. In group 1 (n = 6), the infant periosteum was resected and replaced as an autograft on one side (control), and adult periosteum was transplanted as an isograft on the other (experiment). In group 2 (n = 5), dura was used as the variable. In group 3 (n = 5), combined dura and periosteum were the variables. After 8 weeks, there was complete or near complete bone regeneration in all animals in which infant dura was present. There was minimal to no bone regeneration in defects in which adult dura was present. Unlike dura, periosteum had little influence on the capacity of the bone to regenerate.