The regulation of postnatal skeletal muscle development is complex, involving many integrated biochemical pathways that interact with the environment to ultimately control the rate of protein accretion. The intracellular level of cyclic nucleotides (cAMP/cGMP), which are predominately regulated by phosphodiesterase (PDE), is important for skeletal muscle protein accumulation. To determine whether PDE might play a potential role in postnatal skeletal muscle development, eighteen pairs of specific primers were designed for determining different PDE isozyme mRNA in skeletal muscle tissue and primary cultured myocytes by using RT-PCR. The results showed that seventeen PDE subtypes except PDE8B were expressed at the transcriptional level, with PDE4A, 4B, PDE7A, and PDE9A subtypes displaying stronger expression than others. This is the first report that 18 subtypes of PDE isozymes are expressed in skeletal muscle tissue and primary cultured myocytes, thus implicating their role in postnatal skeletal muscle development.