Objective: To assess the degree of openness of communication about illness and death between patients with advanced cancer and their relatives during the last three months of the patient’s life, and its association with relatives’ characteristics and bereavement distress. Methods: We used data from bereaved relatives of patients with advanced cancer from the prospective, longitudinal, multicenter, observational eQuipe study. Univariate and multivariable linear regression analyses were used to assess the association between the degree of openness of communication (measured using the validated Caregivers’ Communication with patients about Illness and Death scale), the a priori defined characteristics of the relatives, and the degree of bereavement distress (measured using the Impact of Event Scale). Results: A total of 160 bereaved relatives were included in the analysis. The average degree of open communication about illness and death between patients with advanced cancer and their relatives was 3.86 on a scale of 1 to 5 (SE=0.08). A higher degree of open communication was associated with a lower degree of bereavement distress (p=0.003). No associations were found between the degree of open communication and the relatives’ age (p=0.745), gender (p=0.196), level of education (p>0.773), (religious) worldview (p=0.435), type of relationship with the patient (p>0.548), or level of emotional functioning before the patient’s death (p=0.075). Conclusions: Open communication about illness and death between patients and relatives seems to be important, as it is associated with a lower degree of bereavement distress. Healthcare professionals can play an important role in encouraging the dialogue. However, it is important to keep in mind that some people not feel comfortable talking about illness and death