Atrial fibrillation (AF) is the most common chronic arrhythmia in adults and its prevalence is increasing. Due to its serious cardiovascular complications there is a strong need to understand predisposing risk factors to develop effective prevention strategies. There are a few established risk factors but a number of further risk factors have been suggested including obesity, metabolic syndrome, sleep-disordered breathing, and inflammation. The aim of this study was to investigate established and emerging risk factors for AF in a cohort study of 4,267 adults in Busselton, Western Australia, without a history of AF at baseline in 1994/95 who were followed for 15 years for incident AF events. Baseline measurement included questionnaire, clinical assessment and blood sample. A total of 343 (8%) experienced AF during follow-up. Cox regression analysis confirmed advancing age, male sex, taller height, being on hypertension treatment and higher body mass index (BMI) as the major common risk factors (all p < 0.001). However, further modelling showed the effect of being on hypertension treatment may be stronger in women (p = 0.001) and the effect of BMI stronger in men (p = 0.004). After adjustment for these factors, no other factors were strongly related (p < 0.001) although short PR interval, history of valvular heart disease, stroke, chronic obstructive pulmonary disease, lung function and adiponectin level were marginally related (p < 0.05). This cohort study of predictors for incident AF has confirmed the major established risk factors. However, recently suggested potential novel risk factors for AF (inflammation, sleep-disordered breathing, glucose/metabolic disorders) were not confirmed in this study.