P15RS was identified as a novel gene cloned from the human melanoma cell model MLIK6 overexpressing p15INK4b. P15RS has been reported as a negative regulator of cell proliferation in G1 phase. To investigate the localization of P15RS, EGFP-P15RS, a fusion protein with EGFP reporter was constructed and overexpressed in BGC-823 cells. The results showed that EGFP-P15RS protein was distributed in nuclear in interphase (G1, S, G2 phase) of BGC-823 cells. The EGFP-P15RS protein was observed not to localize in chromosome in M phase, suggesting that P15RS might be located in karyoplasm.