© 2022 International Society for Apheresis and Japanese Society for Apheresis.Introduction: Peritoneal fibrosis may progress in peritoneal dialysis (PD) patients to a fatal clinical condition called encapsulating peritoneal sclerosis (EPS). Transforming growth factor (TGF)-β plays a pivotal role in the pathogenesis of peritoneal fibrosis. We aimed to investigate the association among polymorphisms in the gene encoding TGF-β1, which were −509C/T (rs1800469), +869T/C (rs1982073), and +915G/C (rs1800471) in EPS patients. Methods: A total of 16 PD patients who were clinically and radiologically diagnosed with EPS were enrolled and 22 age- and gender-matched PD patients were selected as the non-EPS group. Results: G allele frequency at the rs1800471 gene polymorphism was significantly higher in the EPS group than non-EPS group (p = 0.005). Interestingly, the non-EPS group patients had CC or CG polymorphisms. Conclusion: C allele in TGF-β1 rs1800471 gene polymorphisms might indicate a protective feature in EPS development. Knowing the presence of polymorphism may be effective in selecting renal replacement therapy in patients.