Introduction: As adult urological soft tissue sarcomas (STS) are rare, there have been few recent large-scale studies of these tumors. This report describes a single institutional experience of adult urological STS over 25 years. Patients and Methods: The study population consisted of 25 adult patients with histologically diagnosed STS arising in the urinary tract, male genital system, or retroperitoneum between January 1983 and July 2008. The study endpoint was overall survival. The crude probability of survival was estimated using the Kaplan-Meier method. Uni- and multivariate analysis of differences between patient groups was performed with the log rank test and the Cox proportional hazards model. Results: Overall survival rate at 5 years was 54.2%. On univariate analysis, unfavorable prognostic variables for overall survival were presence of metastasis at diagnosis (p = 0.0005), absence of surgical resection (p = 0.0003), histological subtype of rhabdomyosarcoma (p = 0.0068), and primary organs other than retroperitoneum (p = 0.0410). On multivariate analysis, absence of surgical resection remained a significant predictor of unfavorable prognosis (HR 2.67, 95% CI 1.03–7.76, p = 0.044). Conclusions: Surgical resection, regardless of status of surgical resection margin, contributed to a favorable prognosis in adult patients with locally advanced or metastatic urological STS.