OBJECTIVE: Previous studies have generally shown the effectiveness of prompts to promote stair use in worksites that mainly consist of white-collar workers. The present study tested whether an intervention using prompts is effective in stimulating stair use in two types of worksites: one consisting mainly of white-collar workers and one mainly of blue-collar workers. METHOD: In 2005, elevator and stair use (stair climbing and descent) was monitored in two types of worksites in the Netherlands, namely one office building (n=150 white-collar workers) and one paper factory (n=800 blue-collar workers). The study used a simple time-series design of collecting data in three waves: before, during and after implementation of posters containing prompts stimulating stair use. RESULTS: A total of 6771 choices between stairs and elevator were observed. There was a significant difference between stair use at baseline and during the poster intervention in both types of worksites. There was no worksite-by-intervention interaction, implying that the prompts were equally effective in both types of worksites. After removal of the posters stair use decreased significantly to a level that was not significantly different from baseline. CONCLUSION: Stair use can be positively influenced in both blue- and white-collar workers by a short-term low-cost intervention using prompts on posters.