Purpose: Retroperitoneal soft tissue sarcomas are rare tumors. Studies characterizing long-term follow-up and patterns of recurrence are limited. The purpose of this analysis is to identify patterns of recurrence and prognostic factors associated with long-term survival after resection of retroperitoneal soft tissue sarcomas. Methods: Between July 1, 1982, and June 30, 1990, 198 adult patients were identified from our prospective soft tissue sarcoma database carrying the diagnosis of retroperitoneal soft tissue sarcoma who were eligible for ≤5 years of follow-up. Of these, 48 patients (25%) were documented to be alive ≤ 5 years from the time of operation. Statistical analysis was by log-rank or Wilcoxon test for univariate analysis. Multivariate analysis was by the Cox model. Results: The recurrence rate during the follow-up period was approximately 5% per year from the time of initial operation. Of the patients who were disease-free for ≤ 5 years from initial surgery, 40% recurred by 10 years. Radiation therapy was the only factor significant (P = .02) for a reduction in the risk of local recurrence. Age ≤ 50 years and high-grade tumors were significant factors (P= .003 and .009, respectively) for an increased risk of distant metastasis. Incomplete gross resection was the only factor significant for an increased risk of tumor mortality (P = .003). Conclusion: Complete surgical resection at the time of primary presentation is likely to afford the best chance for long-term survival. With long-term follow-up, it is clear that recurrence will continue to occur, and a 5-year disease-free interval is not a cure. Patients with an incomplete initial resection, age less than 50 years, and high-grade tumors are candidates for investigational adjuvant therapy.