This pilot study highlighted some of the methodological issues involved in conducting a randomized controlled trial of cognitive-behavioural approach to physiotherapy with acute Low back pain (LBP) patients who showed signs of psychological distress. It also enabled calculation of sample sizes, for the main study, to detect clinically important differences in outcome measures. Acute LBP patients with signs of psychological distress (n = 12) were recruited and randomized to one of two interventions: (i) physiotherapy + cognitive-behavioural therapy (CBT); (ii) physiotherapy. Outcome measures of pain and disability were taken at the beginning and after six treatment sessions. The results of the pilot showed no significant differences between the groups at post-intervention period. Sample size calculations showed that 62 subjects would need to be recruited to detect clinically meaningful changes in outcome measures. Some of the methodological issues identified included potential bias, with the same therapist conducting both arms of the study, and differences in time with the therapist between the two groups. A non-therapeutic intervention will be added in order to control for therapist attention time. The main study will have a longer-term follow-up period of 6 and 12 months. Outcome measures of the number of sick days off work will be included to calculate the cost effectiveness of the programme.