This study attempted to assess the degree of knowledge of the diagnosis, and the attitude towards that information, in a group of terminally ill cancer patients. We also tried to determine the influence of the knowledge of the diagnosis on other patient psychosocial needs. We assessed 97 patients (64 in an oncology service, 33 in a palliative care unit) by means of a semistructured personal interview, and a psychosocial needs questionnaire. Data collected showed that 68% of patients had not been informed of their diagnosis; 60% of this group had a high degree of suspicion of their diagnosis, but 42% of noninformed patients did not want to receive more information. Information on diagnosis appears to be beneficial in establishing satisfactory relationships and communication between patients and relatives and staff. We have tried to answer the most relevant issues related to diagnosis disclosure in our clinical setting, questioning the feasibility of truth telling within our cultural boundaries.