Dialysis-related amyloidosis (DRA) is characterized by the deposition of amyloid consisting of beta2microglobulin in the musculoskeletal system, causing carpal tunnel syndrome, destructive spondyloarthropathy, and/or bone cysts. Increased cystic radiolucency of the bones and tendon thickening due to inflammation are common findings in DRA. We have developed a new dialysis method, extendedhours hemodialysis without dietary restrictions for the aim of improving both hypertension and malnutrition. We retrospectively evaluated the clinical effects of dialysis time on the risk for developing of DRA. The study subjects were all of the 30 patients who had received this treatment for more than 11 years. They were divided into two groups according to the weekly dialysis hours: 15 patients ≥ 16.5 hours/week (L-group) and 15 patients ≤ 15.5 hours/week (S-group). Plain x-ray imaging and ultrasonography were used to assess cystic radiolucency of the bones and thickness/diameter of the soft tissues. The proportion of the carpal bone cystic radiolucency was lower in the L-group. The severity of median nerve compression at the wrist was significantly less in the L-group (right hand: p = 0.0082, left hand: p = 0.0137). Multivariate regression analysis showed that dialysis time was a predictor of median nerve compression (β = −0.559, p = 0.005). In conclusion, extended-hours hemodialysis without dietary restrictions contributes to lower the risk for developing of DRA at the wrist. We therefore propose that extended-hours hemodialysis without dietary restrictions is a preferred method which maintains the patients' quality of life compared with the conventional hemodialysis method.