OBJECTIVES: To examine if receiving a pedometer along with an intervention toolkit is associated with increased physical activity, aerobic fitness and better self-rated health among individuals with low levels of physical activity or fitness. METHODS: The intervention was nested in the Danish Health Examination Survey (DANHES) and carried out in 2008. Participants were randomly assigned to either a pedometer group (n=326) or a control group (n=329). Physical activity, aerobic fitness, and self-rated health were measured at baseline and at 3-month follow-up, and differences were tested by Wilcoxons signed rank tests and Chi-squared tests. RESULTS: At follow-up, no significant differences in physical activity, aerobic fitness and self-rated health were found between the groups. However, the oldest participants in the pedometer group reported significantly more walking time compared to the controls (controls=368min/week, pedometer group=680min/week, P=0.05). Among participants who completed the intervention, a significant effect on total walking time was observed (median difference=225min/week, P=0.04). CONCLUSIONS: The results suggest that receiving a pedometer and along with an intervention toolkit can increase walking time in older individuals, but not in younger individuals. Thus, this type of intervention offers great potential for promoting physical activity in older individuals. Trial registration number: NCT01071811.Copyright © 2012 by Elsevier Inc. [ABSTRACT FROM AUTHOR]