Context: Breathlessness is a major cause of suffering and distress, and little is known about the trajectory of breathlessness near death. Objectives: To determine the trajectory and clinical-demographic factors associated with breathlessness in the last week of life in patients receiving specialist palliative care. Methods: This was a prospective, longitudinal cohort study using national data on specialist palliative care from the Australian Palliative Care Outcomes Collaboration. We included patients in the Australian Palliative Care Outcomes Collaboration who died between July 1, 2013 and June 30, 2014 with at least one measurement of breathlessness on a 0-10 numerical rating scale in the week before death. The trajectory and factors associated with breathlessness were analyzed using multivariate random-effects linear regression. Results: A total 12,778 patients from 87 services (33,404 data points) were analyzed. The average observed breathlessness was 2.1 points and remained constant over time. Thirty-five percent reported moderate to severe distress (numerical rating scale ≥4) at some time in their last week. Factors associated with higher breathlessness were younger age, male gender, cardiopulmonary involvement, concurrent fatigue, nausea, pain, sleeping problems, higher Australia-modified Karnofsky Performance Status, and clinical instability in the multivariate analysis. Respiratory failure showed the largest association (mean adjusted difference 3.1 points; 95% confidence interval, 2.8-3.4). Conclusion: Although breathlessness has been reported to worsen in the last months, the mean severity remained stable in the final week of life. In specialized palliative care, one in three people experienced significant breathlessness especially in respiratory disease.