INTRODUCTION: Children with solid organ tumours often present for curative surgery. Even with the best surgical technique, micrometastases can occur. Preclinical studies support the postulation that neuraxial anaesthesia maintains the body's immune and inflammatory milieu against metastasis. However, human retrospective adult studies showed varying results, and no study has been done in children. We aimed to find out if intraoperative epidural, perioperative opioid and volatile dose are associated with relapse-free survival (RFS) in children with solid organ tumours. METHODS: This is a retrospective cohort study of 126 children from a tertiary paediatric unit who were diagnosed with solid organ tumours (neuroblastoma, hepatoblastoma or sarcoma) over a 16-year period. RFS, stratified by tumour subtypes, was estimated using the Kaplan-Meier method. Adjusted hazard ratios (aHRs) were obtained from multivariable Cox regression models after taking potential covariates into account. RESULTS: Of 126 children with solid organ tumours (51.6% neuroblastoma, 34.9% sarcoma and 13.5% hepatoblastoma), 53.2% received combined general anaesthesia (GA)/epidural. A total of 21 (31.3%) and 20 (33.9%) patients relapsed during the study period in the combined GA/epidural group and the GA alone group, respectively. Patients with sarcoma receiving combined GA/epidural had a clinically meaningful lower risk of relapse compared to patients receiving GA alone (aHR 0.51, 95% confidence interval 0.14-1.79), although this was not statistically significant. CONCLUSION Our study demonstrated some clinically meaningful associations, especially in paediatric sarcoma patients. Overall, however, there was no statistically significant association between epidural use and an improved RFS.