Self-help interventions in mental health are increasingly seen as one way of overcoming problems with access to psychological therapy, but there is insufficient evidence of effectiveness in routine care settings. This paper investigates the process and outcome of a non-guided self-help manual for anxiety and depression compared to a waiting list control in a primary care setting. Patients with mild to moderate mental health problems were recruited from routine GP referrals to the local Primary Care Mental Health Team. Thirty patients were randomly assigned to either non-guided self-help or a waiting list control group. Patients completed outcome measures at baseline, 6 weeks and 12 weeks. Intention to treat analysis found no significant differences between the two groups on measures of anxiety or depression at 12 weeks. Between 40% to 50% of patients in both groups were no longer clinical cases at the end of the trial. However, there was a high level of satisfaction with the self-help manual. Within the limitations of the small sample size, the study does not support the hypothesis that non-guided self-help is superior to waiting list control in the treatment of anxiety and/or depression in primary care.