Objective: This study aimed at exploring managers' understanding of workplace health promotion and experiences of workplace health promotion activity within small and medium-sized enterprises. Design: A Heideggerian interpretive phenomenological methodology was adopted. Setting: This study was undertaken with small and medium-sized enterprise managers from a Health and Social Care Trust area of Northern Ireland. Method: In-depth telephone interviews were carried out with a purposive sample of 18 small and medium-sized enterprise managers. Data was analysed using Benner's strategy for data analysis. Results: "Workplace health promotion as a symbiosis of health and business' emerged as a main theme from the data. Participants considered workplace health promotion as a key means of harnessing the potential of both their business and their employees: providing protection from harm and opportunities for health improvement for employees and affording protection for the viability and reputation of the business. Participants also viewed themselves as holding a pivotal role in the development and implementation of workplace health promotion activities. Conclusion: Strategies focussing on employee health alone as a separate entity to the business agenda are likely to be ineffective for raising awareness of workplace health promotion activity within small and medium-sized enterprises. Findings suggest an integrated ecological approach needs to be reflected within policy and practice that extends beyond the individual employee. A revised programme planning framework, based upon the work of Green and Kreuter, identifies areas that health promotion practitioners need to consider for more meaningful engagement with workplace health promotion activity by managers to take place within the small and medium-sized enterprise setting. (Contains 1 table and 1 figure.)