An experimental evaluation of a safer sex promotion leaflet was undertaken to assess its capacity to change antecedent cognitions of condom use. The leaflet was identified in a previous study as addressing research-based cognitive antecedents of condom use. A pre-post-test experimental study including three conditions was conducted: (a) presentation of the leaflet; (b) presentation of the leaflet plus incentive for systematic processing; (c) no-leaflet control. The leaflet was evaluated in terms of its capacity to change eight cognitive correlates of condom use identified in a recent meta-analysis. The sample consisted of 230 tenth-grade students. Following baseline assessments, leaflet-induced change was measured immediately following the intervention and at a follow up 4 weeks post-intervention. The target leaflet alone did not result in significant changes in the cognitive antecedents of condom use compared with the control condition. However, in combination with an incentive for systematic processing, the target leaflet had a greater impact on cognitive antecedents than the no-leaflet control condition. The findings are discussed with regard to the development and evaluation of research-based health-promotion materials.