Purpose: This study was to examine the relationship between mental health status and suicidal thinking among cancer patients. Methods: The data set of the 4th Korea National Health and Nutrition Survey (2009) was used and 230 subjects with cancers were included in the present study. Using SPSS/WIN 18.0 program, data were analyzed with descriptive statistics, ${chi}^2$ test and logistic regression analysis. Results: About one-third of subjects had stress, symptoms of depression and suicidal thinking. Female had more suicidal thinking than male (${chi}^2$=5.44, p=.020). In addition, subjects with high income level had more thinking about suicide compared with those in low income level (${chi}^2$=7.54, p=.023). There was a significant difference in suicidal thinking according to the educational levels (${chi}^2$=13.25, p=.004). In the logistic regression analysis, it was indicated that gender, depression and stress were significant predictors on suicidal thinking, accounting for 26.7~38.1%. Conclusion: From the findings in this study, it was suggested that the healthcare providers should try to improve their mental health status in order to prevent suicidal thinking among the individuals diagnosed with cancer.