Objective: To compare rates of stair climbing in a high and low socioeconomic (SE) area, and to assess the efficacy of a stair climbing intervention in each area. Methods: From March to May 2009 ascending stair/escalator choices (N= 20,315) were observed in two underground train stations located in a high, and low, SE area of Glasgow. Baseline observations preceded a 4-week intervention in which posters, promoting stair choice, were installed. Follow-up observations were collected 1. week after poster removal. Results: Baseline stair climbing rates were 12.2% and 7.1% at the high and low SE stations, respectively. Overall, pedestrians at the high SE station were around twice as likely to climb the stairs as those at the low SE station (odds ratio [OR] = 1.91, 95% confidence interval [CI] = 1.70-2.15). Across sites, the rate of stair climbing was higher during the intervention relative to baseline (OR = 1.48, CI = 1.34-1.63) and remained elevated at follow-up (OR = 1.24, CI = 1.11-1.39). Absolute increase in stair climbing was similar at both stations (high SE, +. 4.7%; low SE, +. 4.5%), indicating equivalent poster effects in each area. Conclusion: Pedestrians in lower SE areas appear less likely to climb stairs than pedestrians in high SE areas. Nevertheless, a stair climbing intervention was equally effective in both areas.