<p><strong>Background/Objective:</strong> Although some studies conducted in Western cultures have identified positive influences of social support on the psychological and physical states of elderly women with breast cancer, few studies have investigated the relationships between social support and its effects on health outcomes in elderly Japanese women with breast cancer. The purpose of this study was to describe and investigate the relationships among social support, social support network, and psychological and physical states among elderly Japanese women with breast cancer.</p><p><strong>Methods:</strong> Elderly Japanese women with breast cancer (n=65) participated in the study. Measures used in this study were the Japanese versions of instruments with established reliability and validity: (1) the Social Support Scale for Japanese Elderly (SSSJE); (2) the Visual Analogue Scale for Social Support (VASSS); (3) the General Health Questionnaire (GHQ) and (4) the Physical States Interview Form (PSIF). Data analysis included descriptive, t-tests, and Pearson’s correlations.</p><p><strong>Results</strong>: Descriptive statistics showed that the size of the social support network ranged from 2 to 34 (M=9.09; SD=6.57). Comparisons of psychological states showed a significant difference between the women who were over and under 70 years old. Psychological states significantly correlated with social support network and conflict among elderly Japanese women with breast cancer.</p><p><strong>Conclusions: </strong>The results reveal that there are significant relationships among social support, social support network, and psychological and physical states among elderly Japanese women with breast cancer. The results reveal that there are significant relationships among social support, social support network, and psychological and physical states among elderly Japanese women with breast cancer. Nurses should provide information on social support as an important factor to help elderly Japanese women with breast cancer.</p>