Background and Objective: The ability of breaking bad news to patients, especially to patients diagnosed with cancer is one of the challengeable issues in the field of medicine. On this basis, this study was designed to assess physicians' performance as well as importance of their training on how to deliver bad news to patients diagnosed with cancer.
 Materials and Methods: This was a prospective cross-sectional study for assessing physicians’ performance in delivering bad news. The hematologists and oncologists from Imam Khomeini and Shariati hospitals, Tehran, Iran, were included in the study. A questionnaire for physicians (SPIKES model) which comprised six statements was used to evaluate their performance. The time of breaking the cancer diagnosis news to the patients by the physicians and educational records were evaluated with the average score of the physicians in relation to each statement.
 Results: Totally, 12 physicians participated in the study. There was no significant difference between the statements and age or gender (P>0.05); but there was a significant relationship between ending the discussion (conversation), summarizing the content, and using the word "cancer” during the conversation (P<0.05). Additionally, there was significant correlation between the time spent on informing the patient about the cancer diagnosis and concluding the discussion and summarizing the statements (P<0.05).
 Conclusion: Guidelines which are introducing the most harmless methods for delivering bad news with minimal negative effects on the patients’ mental health can be helpful for the medical staff, so that they can perform this important task with less stress and minimum complications for the patients.