Background and Methods: Anthroposophic treatment for anxiety disorders includes special artistic and physical therapies and special medications. We conducted a prospective cohort study of 64 consecutive adult outpatients starting anthroposophic treatment for anxiety disorders under routine conditions. Main outcomes were Anxiety Severity (physician and patient ratings 0–10), Self-rating Anxiety Scale (0–100), Center for Epidemiological Studies Depression Scale, German version (CES-D, 0–60), and SF-36 Mental Component Summary. Results: Mean age was 42.3 years. Most frequent diagnoses were generalized anxiety disorder (44% of patients, n = 28/64) and panic disorder (39%). Median disease duration was 4.5 years. The anthroposophic treatment modalities used were medications (56% of patients), eurythmy therapy (41%), art therapy (30%), and rhythmical massage therapy (3%). Median number of eurythmy/art/massage sessions was 12, median therapy duration was 120 days. From baseline to six-month follow-up, all outcomes improved significantly; average improvements were: Physician-rated Anxiety Severity 3.60 points (95% confidence interval 2.97–4.22, p < 0.001), patient-rated Anxiety Severity 3.50 (2.88–4.12, p < 0.001), Self-rating Anxiety Scale 11.88 (7.70–16.05, p < 0.001), CES-D 8.79 (5.61–11.98, p < 0.001), and SF-36 Mental Component 9.53 (5.98–13.08, p < 0.001). All improvements were maintained until last follow-up after 24 months. Conclusions: Patients with anxiety disorders under anthroposophic treatment had long-term improvements of symptoms and quality of life.