Background: Hypothesizing that statins may be useful as adjuvant treatment for renal anemia, we examined the association between statin prescription (Rx) and erythropoiesis-stimulating agent (ESA) hyporesponsiveness in Japanese hemodialysis (HD) patients prescribed ESAs. Methods: We examined 3,602 patients in 60 HD facilities dialyzed 3 times/week for ≥4 months from the Japan Dialysis Outcomes and Practice Patterns Study phases 3-5 (2005-2015). Statin Rx was reported at the end of a 4-month interval (baseline) for each patient. ESA hyporesponsiveness in the subsequent 4 months was then defined as a binary indicator (mean hemoglobin [Hgb] level <10 g/dL and mean ESA dose >6,000 units/week) and separately as the ESA resistance index (ERI; mean ESA dose/[dry weight × mean Hgb]). We used adjusted logistic and linear regressions to evaluate the associations between statin Rx and ESA hyporesponsiveness. Results: At baseline, 16.2% of patients reported statin Rx; 12.8% were classified as having ESA hyporesponsiveness during 4 months of follow-up. Compared to patients without statin Rx, patients with statin Rx had lower odds of ESA hyporesponsiveness (OR 0.87; 95% CI 0.66-1.15). Similarly, the ERI was lower for those with statin Rx than without (ratio of means, 0.94; 95% CI 0.89-0.99) after adjustment for possible confounders. Conclusions: Our results suggest that statins may slightly reduce ESA hyporesponsiveness in HD patients. However, any causal inference is limited by the observational study design and unmeasured compliance with statin Rx.