Chinese family members play an important role in end-of-life decision making. Culturally, they may believe that a patient's awareness of a poor prognosis could harm his or her well-being, and thus they may avoid telling the truth to the patient. To examine this cultural belief empirically, this study aimed to explore the relationships among the patient's awareness of the prognosis, the family's awareness of the prognosis, the patient's anxiety, and difficulty in communicating with family members. Clinical data mining was the research method. Clinical records of deceased cancer patients in the palliative care unit of a hospital during 2003-2005 were reviewed, and 935 patients were included in this study. Logistic regression analyses indicated that patients who did not have a clear awareness of their prognosis were more likely to experience anxiety (odds ratio [OR] = 1.44, 95% CI = 1.14-1.82, p = 0.002) and difficulty communicating with family members (OR = 2.11, 95% CI = 1.62-2.76, p < 0.001). Patients whose family members were less aware of the prognosis were more likely to experience difficulty communicating with family members (OR = 4.48, 95% CI = 1.93-10.42, p < 0.001). This study further suggests that awareness of prognosis may not harm Chinese patients. Instead, unrealistic incomplete awareness of prognosis by patients and family members may be associated with patient anxiety and difficulty communicating.