Objectives: The aim of this study was to illustrate the contribution of stakeholder engagement to the impact of health technology assessment (HTA) using an Irish HTA of a national public access defibrillation (PAD) program.Background: In response to draft legislation that proposed a PAD program, the Minister for Health requested that Health Information and Quality Authority undertake an HTA to inform the design and implementation of a national PAD program and the necessary underpinning legislation. The draft legislation outlined a program requiring widespread installation and maintenance of automatic external defibrillators in specified premises.Methods: Stakeholder engagement to optimize the impact of the HTA included one-to-one interviews with politicians, engagement with an Expert Advisory Group, public and targeted consultation, and positive media management.Results: The HTA quantified the clinical benefits of the proposed PAD program as modest, identified that substantial costs would fall on small/medium businesses at a time of economic recession, and that none of the programs modeled were cost-effective. The Senator who proposed the Bill actively publicized the HTA process and its findings and encouraged participation in the public consultation. Participation of key stakeholders was important for the quality and acceptability of the HTA findings and advice. Media management promoted public engagement and understanding. The Bill did not progress.Conclusions: The HTA informed the decision not to progress with legislation for a national PAD program. Engagement was tailored to ensure that key stakeholders including politicians and the public were informed of the HTA process, the findings, and the advice, thereby maximizing acceptance. Appropriate stakeholder engagement optimizes the impact of HTA.