We compared the effect of a group-based 12-week supervised exercise programme, i.e. aerobic and resistance exercise, and group sports, with that of the same programme combined with cognitive-behavioural training on physical fitness and activity of cancer survivors. One hundred and forty seven cancer survivors (all cancer types, medical treatment >or=3 months ago)were randomly assigned to physical training (PT, n=71) or PT plus cognitive-behavioural training (PT+CBT, n=76). Maximal aerobic capacity, muscle strength and physical activity were assessed at baseline and post-intervention. Analyses using multilevel linear mixed-effects models showed that cancer survivors' physical fitness increased significantly in PT and PT+CBT from baseline to post-intervention. Changes did not differ between PT and PT+CBT. Physical fitness of cancer survivors was improved following an intensive physical training programme. Adding a structured cognitive-behavioural intervention did not enhance the effect.