Abstract Context The physician orders for life-sustaining treatment (POLST) paradigm allows health care professionals to document the treatment preferences of patients with advanced illness or frailty as portable and actionable medical orders. National standards encourage offering POLST orders to patients for whom clinicians would not be surprised if they died in the next year. Objectives To determine the influence of cause of death on the timing of POLST form completion and on changes to POLST orders as death approaches. Methods This was a cohort study of 18,285 Oregon POLST Registry decedents who died in 2010–2011 matched to Oregon death certificates. Results The median interval between POLST completion and death was 6.4 weeks. Those dying of cancer had forms completed nearer death (median 5.1 weeks) than those with organ failure (10.6 weeks) or dementia (14.5 weeks; P  < 0.001). More than 90% of final POLST forms indicated orders for no resuscitation and 65.1% listed orders for comfort measures only. Eleven percent of the sample had multiple registered forms during the two years preceding their death, with the form completed nearest to death more likely than earlier forms to have orders for no resuscitation and comfort measures only, although some later forms did have orders for more treatment. Conclusion More than half of POLST forms were completed in the final two months of life. Cause of death influenced when POLST forms were completed. POLST forms changed in the two years preceding death, more frequently recording fewer life-sustaining treatment orders than the earlier form(s).