Purpose: This study is to examine the effect of electrical muscle stimulation therapy on chronic knee pain for aged. Method: Design was randomized one-group pretest-posttest design. Samples were total 15 elderly on 60 years old and above with chronic knee pain. Measures were S-F McGill Pain Questionnaire and Arthritis Impact Measurement Scale for knee pain. Electrical muscle stimulation therapy, experimental treatment was applied on chronic knee pain for 4 weeks, 3 times/week, 15 min/time. Data were collected from half March 2005 to May 2005. Data were analyzed using SPSS PC+ 12 version. Descriptive statistics was used for analysis of general characteristics in sample, and paired t-test was used to analysis the effect of electrical muscle stimulation therapy. Results: After receiving the electrical muscle stimulation therapy chronic knee pain was significantly decreased (t=-29.163, P=.000 in S-F MPQ; t=-37.005, P=.000 in AIMS). Conclusion: Electrical muscle stimulation therapy can be a better effective primary nursing intervention on chronic knee pain for aged in community.