Epilepsy is characterized by the presence of spontaneous episodes of abnormal neuronal discharges and its pathogenic mechanisms remain poorly understood. Recently, we found that the expression of creatine kinase (CK) was markedly decreased in an epilepsy animal model using proteomic analysis. A human CK gene was fused with a HIV-1 Tat peptide to generate an in-frame Tat-CK fusion protein. The purified Tat-CK fusion protein was efficiently transduced into PC12 cells in a time- and dose-dependent manner when added exogenously to culture media. Once inside the cells, the transduced Tat-CK fusion protein was stable for 48 h. Moreover, the Tat-CK fusion protein markedly increased endogenous CK activity levels within the cells. These results suggest that Tat-CK provides a strategy for the therapeutic delivery of proteins in various human diseases including the delivery of CK for potential epilepsy treatment.