Caveolae are formed by the caveolin (CAV) family of proteins, CAV-1, -2, and -3. CAV-1 and -2 are co expressed in many cell types, whereas CAV-3 is muscle-specific and mutation of the CAV-3 gene causes muscular dystrophy. CAV-3 has also been detected in brain astroglial cells and in peripheral nerves along with CAV-1. Therefore, we sought to determine whether CAV-3 protein is expressed in developing peripheral nerves by using immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR). We found that CAV-3 immunoreactivities (IRs) were Localized in the myelin sheath during peripheral nerve development. CAV-3 IRs were intense during the early postnatal stage, but decreased as the peripheral nerves matured at postnatal weeks 3-5. CAV-3 mRNA expression was also markedly decreased during postnatal development. Because the expression pattern of CAV-3 IRs was opposite that of CAV-1 IRs. CAV-1 and -3 might be involved in different phases of peripheral nerve myelination and play complementary roles in myelin maturation and peripheral nerve development.