Evidence of the effectiveness of health promotion to support decision-making has become increasingly important to health promotion practitioners and policy-makers. Primary research on effectiveness, however, is not always easily accessible. This study aimed to contribute to strategies for facilitating access to this research by exploring the development and implementation of search strategies for identifying effectiveness research, in the area of sexual health promotion, on five commonly used electronic databases. Firstly, search strategies to locate all available research were developed; secondly, the implications of restrictions on the extent of searcliing were investigated. Undertaking systematic searching was complex and time-consuming. Although useful ways to reduce the effort involved were identified, in the context of conducting systematic reviews, these came with 'trade-offs' in terms of the number of potentially important studies missed. These findings suggest an urgent need for wide dissemination of search strategies and specialised registers of health promotion studies. This study is part of an ongoing programme of work on facilitating evidence-based health promotion, and this the third and final paper in a series published in three consecutive issues of the HEJ.