To assess the efficacy of self-management programs it is important to know what behavioural changes take place. This paper assesses whether including self-treatment guidelines (action plans) in a self-management program for adult asthmatics, leads to greater behavioural changes than a program without these guidelines. Patients were randomised into a self-treatment group (n=123) or an active control group (n=122). All subjects received self-management training. Discussed topics included the pathophysiology of asthma, medication and side-effects, triggers, symptoms, smoking, physical exercise, and compliance. The only difference was that the self-treatment group received instructions about self-treatment of exacerbations and the control group did not. At 1 year of follow-up asthma-specific self-efficacy expectancies, outcome expectancies, and asthma-specific knowledge improved significantly in all patients. Only self-treatment group patients demonstrated favourable changes in generalised self-efficacy, social support, and self-treatment and self-management behaviour, in case of a hypothetical scenario of a slow-onset exacerbation. We conclude that our self-management program is effective in changing the behavioural variables, and including self-treatment guidelines (action plans) has added benefit.