Background: Infantile soft tissue sarcoma (STS) has been associated with worse survival than STS in older children. Age, histology, molecular phenotype and treatment adjustment according to age may affect the outcome of patients with rhabdomyosarcoma (RMS) diagnosed during the first year of life. Methods: The records of 5 trials and one registry, conducted by the Cooperative Studiengruppe (CWS) between 1981–2016, were reviewed to identify children diagnosed with RMS during the first year of life. Patient characteristics, treatment data and outcome were evaluated. Results: A total of 155 infants ≤ 12 months with histological diagnosis of RMS were identified, including 115 cases of embryonal RMS (RME), 38 cases of alveolar RMS (21/25 PAX7/3:FOXO1-positive (PF+)), 1 case of botryoid RMS and 1 case of spindle-cell RMS. 144 infants presented with localized disease (LD); 11 with metastatic disease (MD). 150 children received age- and weight-adapted chemotherapy (1/3 dose reduction in infants ≤6 months): VAIA/VACA/CEVAIE (n = 100), IVA/VA/VAC/other (n = 50). Resections were achieved R₀ (n = 64), R₁ (n = 37), R₂ (n = 37) and biopsies (n = 17). Adjuvant radiotherapy (RT) was administered to 37 children. After a median follow-up of 7.55 years [0.24- 30], the 5-year overall survival (OS) and event-free survival (EFS) rates were 66% and 49% for the whole group. Significant prognostic factors were LD (OS 69% vs 12% in MD, p = 0.000), tumor size and resection status. For patients with LD, tumor size and best resection (R₀/R₁/R₂) were no prognostic factors and RT did not improve survival. 2^nd malignancy occurred in 6 infants. OS and EFS rates of newborns (≤1 month, n = 15) were significantly worse (31% and 17%, respectively) compared to those > 1 month and ≤ 12 months (n = 140, OS 69% and EFS 52%, p = 0.001 and 0.001). Children with RMA (41% and 24%) and/or PF+-RMS achieved significantly worse regarding OS and EFS (36% and 19%) than those diagnosed with RME (72% and 56%; p = 0.018 and 0.003). Conclusions: Survival of infants with RMS is comparable to older children. Metastatic disease, RMA histology/ PF+ status and age below 1 month are factors relevant for inferior outcome. RT did not improve survival in LD.