Protein kinase C (PKC) is a key enzyme in regulating a variety of cellular functions. PKCθ is the most abundant PKC isoform expressed in skeletal muscle. However, the functional role of PKCθ linked to muscle regeneration has not yet been identified. Using reverse transcription (RT)-PCR and immunofluorescence analysis, we investigated the expression patterns of PKCθ in normal and regenerating tibialis anterior (TA) muscles in the rat. The amount of PKCθ mRNA in the muscle increased from the 4th to 6th post-surgical day. Immunofluorescence revealed PKCθ protein in quiescent satellite cells identified by c-Met. PKCθ immunoreactivity was not observed in many proliferating satellite cells by labeling with BrdU in the regenerating muscle. At 4, 6 and 10 days postsurgery, PKCθ immunoreactivity was observed in half the differentiating satellite cells labeling with myogenin. After 4 and 6 days, the localization of PKCθ coincided with those of Pax7 and TGF-β. Thus, PKCθ may play an important role in inhibiting differentiation and maintaining the quiescent satellite cells in muscle regeneration.