Objective: A naturalistic, prospective study analyzed the effectiveness of long-acting injectable risperidone (LAIR) in psychotic outpatients. Methods: All outpatients (n = 53), affected by Schizophrenia and other Psychotic Disorders, who have begun LAIR at the Mental Health Service of Modena from December 1, 2005 to December 1, 2006, were collected. Exclusion criteria: concomitant oral antipsychotic therapy at the 12th weeks (n = 16 patients) and treatment discontinuation (n = 12). The reasons of drop-out were analyzed. Clinical and demographic characteristics of outpatients (n = 25), motivations, implementation and adverse effects of LAIR treatment were evaluated. Main outcome: the improvement of symptoms (25% reduction of BPRS and CGI-S scale score from baseline) and functioning level (50% increase of GAF scale score from baseline) at 6th (T6) and 12th (T12) month of LAIR therapy. Secondary outcome: reduction of the hospitalization days during the 1-year LAIR treatment in comparison to the previous year ones of the same patients. Results: The final BPRS, CGI-S and GAF scores both at T6 and T12 showed a statistically significant difference from baseline (p < 0.0001, t-test). The frequency of improved patients in BPRS, CGI-S and GAF scales were 60%, 68%, 52% at T6, and 72%, 54%, 56% at T12, respectively. Side effects were represented by weight increase (4%), orthostatic hypotension (8%) and EPS (4%). The hospitalization days were statistically significant reduced during the 1-year LAIR treatment in comparison to the previous year ones (p < 0.05, t-test). Conclusion: Our data, limited by the small sample and the naturalistic methodology, suggest that 1-year LAIR treatment may be effective and safe. Psychopharmacology Bulletin. 2010;43(1):39-52.