Background: Trabectedin (Yondelis) is the first marine-derived antineoplastic drug approved in Europe for the treatment of patients with recurrent ASTS or for patients unsuited to receive anthracyclines and ifosfamide. We retrospectively analyzed the RetrospectYon database with patients’ data treated with trabectedin between Jan 2008 - Dec 2011. Methods: Trabectedin was given at the approved dose of 1.5 mg/m² as a 24-h infusion every 3 weeks. Patients who achieved partial response (PR) or stable disease (SD) after 6 cycles could receive maintaining trabectedin treatment. Uni- and multivariate analyses of prognostic factors were performed. Results: 885 patients (486 women) from 26 centers in France with ASTS with a median age of 54 years (range 12-84) were included. Most had leiomyosarcoma (36%), liposarcoma (18%) or synovial STS (11%). At baseline, performance status (PS) was 0 in 26%, 1 in 47% and >1 in 27% of patients. A median of 4 trabectedin cycles (range 1-28) was given as a 2^nd (41%), 3^rd (39%) or ≥4^th (20% of patients) treatment line. Toxic death and unscheduled re-hospitalization occurred in 0.5% and 8% of patients, respectively.The objective response rate was 15% (6 complete and 127 PR), and SD rate was 45.5% (n=403). After a median follow-up of 22.6 months (range 0.03-51.2), the patients who received trabectedin as 2^nd, 3^rd or ≥4^th line had the median PFS of 4.3, 4.2 and 3.4 months, respectively, and the median OS of 12.9, 12.3 and 9.5 months. Multivariate analysis identified liposarcoma, leiomyosarcoma, angiosarcoma, undifferentiated pleomorphic sarcoma (UPS) and trabectedin line as independent prognostic factors for PFS, and UPS, angiosarcoma, rhabdomyosarcoma, gender, PS and trabectedin line for OS. After 6 cycles, 205 of the 273 patients with non-progressive disease received trabectedin as maintenance treatment and obtained a superior PFS (median 11 vs. 7.2 months, p=0.0001) and OS (median 25.1 vs. 16.9 months, p<0.0001) that those who stopped trabectedin after 6 cycles. Conclusions: Patients with ASTS treated with trabectedin had PFS and OS comparable or better to those observed in phase II/III trials. Trabectedin maintenance beyond 6 cycles is associated with improved OS and warrants further exploration.