PURPOSE: This study aimed to investigate perceived medication safety in patients with cancer during transitions of care and identify factors associated with their safety perceptions. METHODS: A secondary data analysis was performed on a cross-sectional survey data of from patients with four types of cancer (i.e., colorectal, lung, prostate, and breast). Perceived medication safety was measured by the sum score of four survey items that assessed patients' feelings about medication safety during transitions of care. Potential associated factors included sociodemographic and clinical factors (i.e., cancer types, taking oral anticancer agents), self-rated health, perceived safety in communicating with clinicians, beliefs about medications, and medication self-management ability. Descriptive statistics, bivariate correlations, and multiple linear regressions were performed. RESULTS: A total of 183 patients were included, with a mean (SD) age of 65.04 (11.07). Participants reported a moderate level of perceived medication safety (mean [SD] = 13.56 [1.85], median = 13, IQR: 12-15). Multiple linear regression analysis revealed that better medication self-management ability (coefficient = 0.29, p < .001), feeling safer in communication with healthcare providers (coefficient = 0.87, p < .001), and having less concern about medications (coefficient = -0.11, p < .001) were significantly associated with higher perceived medication safety. Additionally, younger age (coefficient = -0.03, p = .02) was associated with higher perceived medication safety. The final model explained 43% of the variance. CONCLUSIONS: The study's findings underscore the importance of effective communication and self-management in enhancing medication safety in patients with cancer during transitions of care, particularly for older adults needing additional support.