BACKGROUND As Ewing sarcoma (EWS) can affect children and adults, these patients can be treated at either a pediatric or an adult institution. This study investigated whether differences in therapeutic strategy undertaken in pediatric and adult specialty sarcoma centers correlated with clinical outcome. METHODS Data from patients with localized EWS treated between 1990 and 2005 at tertiary care pediatric and adult institutions were reviewed. RESULTS Fifty-three patients (24 adult and 29 pediatric) were treated. Pediatric patients received a median of 16 cycles of chemotherapy comprised of doxorubicin, vincristine, cyclophosphamide, ifosfamide, and etoposide. Adult patients received a median of 10 cycles of treatment, and a significantly lower total cumulative dose of ifosfamide and cyclophosphamide (P < .0001). There was no difference noted with regard to the total dose of doxorubicin, or in the type of local therapy offered (surgery or radiotherapy, vs both). However, local therapy occurred earlier in pediatric patients compared with adults (3.7 months vs 7.4 months; P = .0003). The 3-year event-free survival (EFS) rate in pediatric and adult patients was 70% +/- 9% and 43% +/- 13% (P = 0.1), respectively. The 3-year overall survival rate was 81% +/- 7.7% and 59% +/- 12% (P = .02) for pediatric and adult patients, respectively. Factors found to be significantly associated with EFS on univariate analysis included pelvic site, cyclophosphamide dose, and time to local therapy. On multivariate analysis, only pelvic disease (hazard ratio [HR] 4.26; P = .018) and time to local therapy (HR, 1.19; P = .002) were found to be significant. CONCLUSIONS Adults with localized EWS have an inferior outcome compared with pediatric patients. This difference may be related to lower doses of alkylating agents and the timing of local therapy.