Purpose: This study examined the effect of marital communication on cancer coping, health promoting behavior, and subjective happiness in elderly cancer patients.Methods: The participants were 88 older patients with cancer living with a spouse for at least one year. Data collected through a questionnaire covering general characteristics, marital communications, cancer coping, health promoting behavior, and subjective happiness were analyzed using descriptive statistics, Pearson’s correlation, and a simple linear regression test using the SPSS 26.0.Results: Marital communications showed a positive correlation with cancer coping (r=.54, p<.001), health promoting behavior (r=.47, p<.001), and subjective happiness (r=.46, p<.001). Positive marital communications had the greatest influence on cancer coping (β=.54, p<.001).Conclusion: The findings suggest that developing nursing interventions that can enhance marital communications between older patients with cancer and their spouses could improve their quality of living.