Objective:To evaluate the applicability of Porthsmouth modified physiological and operative severity score for the enumeration of mortality and morbidity ( PPOSSUM) in predicting the mortality of the patients undergoing hip joint arthroplasty.Methods: A total of 141 patients (75 males and 66females, aged 63.22 years ± 14.45 years on an average)undergoing hip joint arthroplasty during January 2002 and March 2005 were studied retrospectively with P-POSSUM.Their average physiological score and operative severity score were 17.48 ± 5.16 and 12.43 ± 3.05, respectively.The predicted postoperative mortality with P-POSSUM was compared with the observed value. Subgroup analysis was performed to investigate the predictive capability of PPOSSUM. POSSUM scoring system was used as the control.Results: Three patients died after operation in this study actually. The average physiological scores were32.33 ±9.87 in the death group and 17.16 ±4.56 in the survival group. The former was obviously higher than the latter, which showed statistical difference between the two groups (Wilcoxon rank sum test, P＜0.05). Perfect agreement was found between the observed death number and the predicted death number calculated by P-POSSUM( Cochran-Mantel-Haenszel χ2 test, P ＞ 0.05), though POSSUM overestimated the overall mortality.Conclusions: P-POSSUM can predict the mortality accurately in the patients undergoing hip joint arthroplasty,which is superior to POSSUM.