Little is known about the contribution of diet components independent of body composition to persistent fatigue in breast cancer survivors. Therefore, our study aim was to determine the associations among dietary intake and fatigue in relation to and independent of adiposity and physical activity (PA) in breast cancer survivors. Baseline data from 42 breast cancer survivors enrolled in a randomised exercise trial were analysed: fatigue (Functional Assessment of Cancer Therapy for fatigue), diet components (3-day diet record), body mass index, per cent body fat (dual-energy X-ray absorptiometry) and PA (accelerometer). The mean age was 54 ± 9 years with an average body mass index of 30.5 ± 8.1kg/m2. Fatigue was positively associated with % of kcal/day fat intake (r= 0.31, P < 0.05) and inversely related to fibre g/day (r= 0.38, P < 0.05) and carbohydrate g/day intake (r= 0.31, P < 0.05). Mean fatigue was greater for participants eating <25g/day of fibre compared with >25g/day of fibre (15.7 ± 10.8 versus 6.4 ± 3.7, P < 0.005). No significant associations were noted between fatigue and PA or body composition. Diets high in fibre and low in fat are associated with reduced fatigue in breast cancer survivors. The difference in fatigue for low- versus high-fibre diets exceeded the minimal clinically important difference of three units. Prospective studies evaluating the effect of changing diet on fatigue in breast cancer survivors are warranted. © 2012 Blackwell Publishing Ltd.