Retrospective chart reviews of seven adolescent and young adults with autistic disorder treated with fluoxetine alone or in combination with other medications were performed. Patient's ages varied from 9-20 years (M ± SD, = 16 ± 3.87). Fluoxetine doses ranged from 20-80 mg per day (M ± SD of final doses 37.14 ± 21). Duration of treatment ranged from 1.3-32 months (M 18.04 ± 10.39). Patients' symptoms were monitored using the Aberrant Behavior Checklist (ABC) rating scale during every visit. Side effects included initial appetite suppression, vivid dreams, and hyperactivity. Improvement from baseline was seen in four subscales: irritability (21%), lethargy (37%), stereotypy (27%), and inappropriate speech (21%). Lethargy subscales improved significantly during treatment (p < .029). Hyperactivity subscale increased by 14% but did not attain statistical significance. Fluoxetine appears to have important behavioral effects in treatment of clinic-referred autistic children. Future double-blind placebo controlled studies evaluating core and associated symptom response with fluoxetine are warranted.