The primary objective of this study is to review the clinical characteristics of 25 patients in the adult and late adolescent age group, diagnosed and treated with small round cell tumors involving soft tissues (extraosseous Ewing sarcoma, rhabdomyosarcoma, primitive neuroectodermal tumor, and Undifferentiated small round cell tumors). Additionally, survival and prognostic factors influencing the outcome with multimodality treatment are evaluated. There were 19 males (76%) and 6 females (24%). The median age was 26 years (range: 15-56 years). In 9 patients (36%), the tumor was located at an extremity, whereas 16 patients (64%) had central localizations. Tumor size was larger than 10 cm in 7 patients (29.2%). Six patients (24%) had metastatic disease. Twelve patients (48%) received radiation and 16 patients (64%) underwent surgery. Among the resected tumors, 2 were resected with contaminated margins (12.5%), whereas 2 were radically resected and 12 (75%) were resected with wide margins. All patients were given a median of 4 cycles of multiagent chemotherapy (1-14 cycles). With preoperative chemotherapy, complete regression (CR) of the tumor was achieved in 6 patients (24%). In 4 patients (16%), a partial response was obtained. After the completion of multimodality treatment, 12 patients (48%) had a CR. Progression-free (PFS) and overall Survival (OS) for the entire group was 25.0 +/- 10.8% at 1 year and 30.5 +/- 15.5% at 3 years, respectively. Nonmetastatic disease, wide and radical resection, and presence of CR to multimodality treatment were associated with a significantly longer PFS and OS by univariate analysis. By multivariate analysis, CR to multimodality treatment was the only independent predictive factor for a longer OS (p: 0.0036, relative risk [RR]: 23.6, 95% Cl: 2.8; 198.7) and metastatic presentation was the only independent factor predictive for a shorter PFS (p: 0.017, RR. 15, 95% CI: 1.6; 141.2). Large-scale, multicenter studies are required for a better evaluation of the nonpediatric age group with small round cell tumors.