Abstract: Objective To investigate the expression of the phosphorylated P27kip1 and correlation with Non-Hodgkin's lymphomas. Methods The expressions of the phosphorylated P27kip1 was detected in lymphoid nodes by immunohistochemical technique. Results The average labeling indexs (LIs) of phosphorylated P27kip1 in NHLs were significantly higher than those in benign lymphoid nodes (outside of the germinal center). The expression of phosphorylated P27kip1 in aggressive lymphomas was higher than that in indolent group; and the expression of phosphorylated P27kip1 was significantly correlated with expression of Ki-67. The expression of Thr187 phosphorylated P27Kip1 was significantly correlated with expression of P27kip1 while the Ser10 phosphorylated P27kip1 negtively correlated with the expression of P27kip1. Conclusions The high expression of phosphorylated P27kip1 plays key roles in the occurrence and development of NHL; phosphorylated P27kip1 LI and P27kip1 LI could be good parameters to determine the malignance of NHL.