Background: Primary soft tissue sarcomas (STSs) involving the chest wall are uncommon. The aim of this study was to identify factors that influence the prognosis of patients with primary chest wall STS. Methods: The records of 38 patients (23 men and 15 women) who were treated at our institutions during 2002 to 2018 were reviewed. The following variables were evaluated as potential prognostic factors: sex, tumor size, chemotherapy, and completeness of surgical margins. Multivariate analysis was conducted to identify predictors of overall survival (OS) and disease-free survival (DFS). Results: Of the 38 included patients, 5 had low-grade tumors and 33 had high-grade tumors. Five patients required chest wall reconstruction including rib resection. Thirty patients (79%) underwent R0 resection. The 5-year OS and DFS rates were 45% and 27%, respectively. Local recurrence developed in 7 patients. Multivariate analysis identified tumor size (hazard ratio [HR]: 4.13; 95% confidence interval [CI]: 1.05-16.24; P = .04) and R1/2 resection (HR: 3.92; 95% CI: 1.12-13.66; P = .03) as predictors of OS. Conclusions: Prognostic factors for survival included tumor size and completeness of surgical margins. Complete tumor excision is desirable, particularly in cases of early detection.