Many keratinocyte therapy products are in development or have recently been introduced onto the market. Recently new products are constantly produced and approved for clinical use in burn surgery and other chronic wounds. The purpose of this study is to suggest the purity test method for keratinocyte therapy products. In this study, we investigated the cellular impurity test and in-process impurity test for keratinocyte therapy products. For cellular impurity test, the ratio of inactive cell (fibroblast, endothelial cell and melanocyte) to against active cell was detected using real-time PCR and FACS (fluorescent activated cell sorter). Because of unavailability of specific surface marker, cellular impurity results by real-time PCR was more objective than FACS. For in-process impurity test, the amount of residue gentamicin and FBS were detected. A sensitive and robust high-performance liquid chromatographic method with fluorescence detection (HPLC-FLD) was developed for the determination of gentamicin residues in keratinocyte therapy product. Gentamicin is consists of four major components, C1, C1a, C2, and C2a. BSA (bovine serum albumin) residues of FBS were detected by commercial test kit based on ELISA (Enzyme-Linked Immunosorbent Assay).