Objectives: To determine if reuse of hemodialyzers is associated with higher rates of hospitalization and their resulting costs among end-stage renal disease (ESRD) patients. Methods: Noncurrent cohort study of hospitalization rates among 27,264 ESRD patients beginning hemodialysis in the United States in 1986 and 1987. Results: Dialysis in free-standing facilities reprocessing dialyzers was associated with a greater rate of hospitalization than in facilities not reprocessing (relative rate (RR) = 1.08, 95% confidence interval (CI), 1.02–1.14). This higher rate of hospitalization was observed with dialyzer reuse using peracetic/acetic acids (RR = 1.11, CI 1.04–1.18) and formaldehyde (RR = 1.07, CI 1.00–1.14), but not glutaraldehyde (p = 0.97). There was no difference among hospitalization rates in hospital-based facilities reprocessing dialyzers with any sterilant and those not reprocessing. Hospitalization for causes other than vascular access morbidity in free-standing facilities reusing dialyzers with formaldehyde was not different from hospitalization in facilities not reusing. However, reuse with peracetic/acetic acids was associated with higher rates of hospitalization than formaldehyde (RR = 1.08, CI 1.03–1.15). Conclusions: Dialysis in free-standing facilities reprocessing dialyzers with peracetic/acetic acids or formaldehyde was associated with greater hospitalization than dialysis without dialyzer reprocessing. This greater hospitalization accounts for a large increment in inpatient stays in the USA. These findings raise important concerns about potentially avoidable morbidity among hemodialysis patients.