The objective of this study is to evaluate the effectiveness of (guided) self-help in primary care for patients diagnosed with a minor or major mood and/or anxiety disorder. The study population consists of 120 (screened) primary care patients aged 18-65 years with at least one mood and/or anxiety disorder. The primary focus is the reduction of depressive and anxiety symptoms. The self-help courses (Problem Solving Treatment and exposure) took 6 weeks to complete. The self-help group reported slightly better outcomes than the care-as-usual group but these results were not significant: d=-0.18 (95% CI=-2.29 to 7.31) for symptoms of depression and d=-0.20 (95% CI=-0.74 to 2.29) for symptoms of anxiety. For patients with an anxiety disorder only, the anxiety symptoms decreased significantly compared to the care-as-usual group (d=-0.68; 95% CI=0.25 to 4.77). Self-help seems only slightly superior to care-as-usual and therefore might not be an effective tool in general practice. But the lack of results could also be due to our selection of patients or to our selection of GPs (with interest in psychiatric disorders). Nonetheless the promising signals with respect to anxiety disorders warrant further research.