ObjectivesOur primary objective was to determine if more comprehensive advance care planning (ACP) documentation was associated with fewer transfers to hospital in the last year of life. Our secondary objective was to determine the impact of ACP processes and practices on hospital transfers in the last year of life. DesignRetrospective cohort study. Setting and ParticipantsLong-term care (LTC) residents in Ontario, Canada, 65 years and older who died between January 1, 2017, and May 30, 2018, and resided in a participating LTC home. MethodsWe administered a survey to directors of care at LTC homes inquiring about ACP practices. Our exposure of interest was living in a home with comprehensive ACP documentation that includes information beyond preferences for cardiopulmonary resuscitation and hospital transfer. Our primary outcome was the number of transfers to hospital in the last year of life. We fit negative binomial regression models to determine the independent effect of comprehensive ACP and other indicators of ACP quality. ResultsA total of 157 LTC homes with 6637 decedent residents were included in our study; 2942 lived in homes with comprehensive ACP documentation and 3695 had non-comprehensive ACP documents. Comprehensive documentation was not associated with fewer hospital transfers in the final year of life [incidence rat ratio (IRR), 1.00; 95% CI, 0.91–1.09]. ACP documentation update frequency, availability of ACP documents in the electronic medical record, referring to ACP documents during a health crisis, inclusion of resident values in ACP documents, and involvement of a multidisciplinary team were all associated with fewer transfers to hospital during follow-up in the last year of life. Conclusions and ImplicationsACP documents that contain information beyond preferences for cardiopulmonary resuscitation and hospital transfer had no association with transfers to hospital, but high-quality ACP practices and processes were associated with fewer transfers.