The purpose of this study is to develop the GPM-K and test the validity and reliability of it. GPM-K is a multidimensional pain assessment instrument for older adults. One hundred twenty-one community-dwelling old adults aged 65 and older who expressed chronic pain were included. They completed GPM-K. The Korean version of the Brief Pain Inventory (BPI-K), Korean Mini-Mental State Examination (K-MMSE), Geriatric Depression Scale Short Form Korean version (GDSSF-K), Pain Management Index (PMI), and Elderly Life Stress Index (ELSI) were used to further validate the GPM-K. A standardized Cronbach's alpha was 0.92, and average inter-item correlation was 0.32. Of those, who repeated the GPM-K within 2-4 weeks (n=32), Pearson's r correlation of test-retest reliability was statistically significant (r=0.640). Correlation coefficient was highly significant between the GPM-K and mean pain severity of the BPI-K (r=0.726, p<0.001), and between the GPM-K and mean pain interference of the BPI-K (r=0.698, p<0.001), as well. The GPM-K was correlated with the GDSSF-K (r=0.256), the ELSI (r=0.312) and the PMI (r=-0.509). The GPM-K is a valid and useful instrument to assess pain and its related factors for the Korean older adults.