The study investigated the puzzling factors and solutions of family-related barriers to truthfulness with patients with terminal cancer through a nationwide survey conducted in Taiwan. Two-hundred twenty-nine valid questionnaires were retrieved (91.6%) from 250 palliative care workers at 15 Taiwan hospices. Most of the respondents were nursing staff (72.5%), and only 38 respondents were physicians (16.6%). Canonical correlation analysis was used to examine the association between the puzzling factors and solutions, which revealed that the value of the first variate was 0.39 (P < .05). Results showed that the puzzling factors of barriers and canonical loadings were families do not know how to tell the truth (.85), families believe it is unnecessary to tell aged patients the truth (.71), and patients can be happier without knowing the truth (.70). The valid solutions correlated significantly with the above puzzling factors and were ranked in the following order: communicate with and encourage families to accept patients' prognoses (.83), discuss the sickness gently with patients and determine what patients know (.76), and tell the families about the possible emotional reactions in patients and how to provide support (.72). In conclusion, for solving family-related barriers to truthfulness in cases of terminal cancer, the results suggest that health professionals communicate with families first and discuss the possible emotional reactions from patients, give patients enough time to reflect on their sicknesses and discuss further what patients have been told, and then disclose information based on patients' expectations and support them.