People approaching end of life account disproportionately for health care costs, and the majority of these costs accrue in hospitals. The economic evidence base to improve value of care to this population is thin. Natural experiment methods may be helpful in bridging evidence gaps with credible causal estimates from routine data, but these methods have seldom been applied in this field. In primary analysis we evaluated if timely palliative care receipt following emergency hospital inpatient admission impacted length of stay (LOS); in secondary analysis we verified if palliative medicine service (PMS) implementation co-occurred with any changes in in-hospital mortality, and we estimated cost differences associated with any change in LOS. This was a secondary analysis on routinely collected data for acute admissions to public hospitals in Ireland. We used difference-in-differences analysis to exploit the staggered implementation of PMS teams at acute public hospitals in Ireland between 2010 and 2015. We identified palliative care receipt following PMS implementation using ICD-10 codes, and we matched admissions involving a palliative care interaction to admissions in years prior to PMS implementation using propensity score weights. Our primary analytic sample included 4,314 observations, of whom 608 (14%) received timely palliative care. We estimated that the intervention reduced LOS by nearly two days, with an estimated associated saving per admission of €1,820. These analyses were robust to multiple sensitivity analyses on regression specification, weighting strategy and site selection. Proportion of admissions ending in death did not change following PMS implementation. Prompt interaction between suitable patients and palliative care can improve the quality and efficiency of care to this population. Many patients receive palliative care later in the hospital stay, which does not yield cost-savings. Future studies can extend and strengthen our approach with better data, as well as using different methods to understand how to trigger palliative care early in a hospital admission and realise available gains.