Nordic walking (NW), characterized by the use of two walking poles, has positive effects on several muscle groups. Muscle strength and mass decrease with age, and recently, this decrease is defined as sarcopenia. Sarcopenia may be triggered by oxidative stress. We investigated whether changes in the oxidative stress marker, malondialdehyde-modified low-density lipoprotein (MDA-LDL)/LDL-cholesterol (LDL-C) ratio are associated with change in handgrip strength (HGS), which is a useful indicator of sarcopenia, by a 12-week NW exercise among Japanese community-dwelling persons. The present study included 65 women aged 67±7 years and 9 men aged 71±8 years from a rural village. NW exercise of 120 min per week was performed for 12 weeks. Before and at the end of the 12-week intervention, various confounding factors and HGS were measured. 12-week changes in various factors were calculated by subtracting the baseline values from the 12-week values. Changes in HGS and follow-up HGS increased progressively with decreased changes in the MDA-LDL/LDL-C ratio after the 12-week walking exercise (r=-0.32, P=0.006 and r=-0.35, P=0.002, respectively). Multiple linear regression analysis showed that changes in HDL-C (β=0.26, P=0.019) and MDA-LDL/LDL-C ratio (β=-0.32, P=0.004) were significantly and independently associated with changes in HGS. When the data were further stratified by gender, change in the MDA-LDL/LDL-C ratio was significantly and similarly associated with change in HGS in women only. These results suggest that change in MDA-LDL/LDL-C ratio may be a predictor for HGS after a 12-week NW exercise in community-dwelling persons.