Background The workplace has become a key target for health promotion programs aimed at increasing physical activity and preventing chronic disease. One growing area of workplace health promotion programs is pedometer-based initiatives. However, only a few have been evaluated and they often lack a range of measures, long-term evaluation and adequate power. Hence, pedometer workplace programs are being implemented without adequate evaluation of health benefits. To better understand whether these relatively simple health programs offer an avenue for improving population health, a large follow-up study, powered to detect changes in multiple objective health markers was required. Aim The aim of this PhD is to evaluate whether participation in a pedometer-based, physical activity, four-month, workplace health program results in improvements in risk factors for diabetes and cardiovascular disease, immediately after the program and in the long-term (eight-months post completion of the health program). Methods Description of the program: The Global Corporate Challenge® (GCC®) is a corporate organisation that undertakes a world-wide, annual, four-month, pedometer-based workplace health with a target of taking at least 10,000 steps per day. Study Population: 762 Australian adults employed in primarily sedentary occupations and voluntarily enrolled in the GCC® workplace health program were recruited in April/May 2008. Directly after the program (four-months) 79% of participants returned and 76% returned in the long-term (eight-months post program). Data Collection: Data were collected at baseline (prior to the GCC® 2008), at four-months (immediately after completion of GCC® 2008) and in the long-term (eight-months after completion of GCC® 2008). Anthropometric and biomedical measurements were collected by trained staff in the morning at the employee's workplaces. An Internet self-report questionnaire incorporated demographic information, motivation and support for participation, health history, behavioural measures and psychosocial health. Ethics: The Monash University Standing Committee on Ethics in Research involving Humans approved this study. Results The majority of these Australian adults in sedentary occupations were not meeting recommended guidelines for a number of chronic disease risk factors and a substantial proportion were unaware of their increased health risks. Participation in the workplace heath program was associated with immediate improvements in behavioural and anthropometric risk factors for diabetes and cardiovascular disease including physical activity (an increase of 6.5% in the proportion meeting guidelines), sitting time (weekday: -0.6 hours/day; weekend: -0.6 hours/day), blood pressure (systolic: -1.8mmHg; diastolic: -1.8mmHg) and waist circumference (-1.6cm), as well as, well-being (3.5 WHO-Five Well-being Index units) and the mental health (1.5 units for the mental component of SF-12® Health Survey). Eight-months after the completion of the health program, sustained improvements were observed for behavioural and anthropometric risk factors for diabetes and cardiovascular disease including sitting time (weekday: -0.6 hours/day; weekend: -0.4 hours/day) and blood pressure (systolic: -3.8mmHg; diastolic: -2.2mmHg), as well as, well-being (3.4 WHO-Five Well-being Index units). Conclusion Participation in this pedometer-based, physical activity, four-month, workplace health program was associated with immediate (four-months) and sustained (eight-months post program) improvements in psychosocial health and a number of chronic disease risk factors. These results indicate that such programs can have an immediate and long-term benefit and thus, a potential role to play in population prevention of chronic disease.