Abstract Background and Aims Japan is currently moving towards an unprecedented aging society and chronic dialysis patients as well. As Aging population increases, in chronic dialysis patients as well, Mild cognitive impairment (MCI) and dementia cases are on the rise, and increasing burden on existing dialysis facilities. Our hospital has not only the outpatient department of Internal medicine, but also peritoneal and hemodialysis facilities, and Regional Dementia Center. We have accepted chronic dialysis patients, in our medical center and elderly ward, who are usually unable to maintain hospitalization or outpatient maintenance dialysis with cognitive impairment by collaborating with psychiatrists. Rehabilitation was instructed in all the patients by physiotherapists for the purpose of improving ADL. We investigated the current status of our PD patients, HD patients who experienced PD, and HD patients with Alzheimer’s type dementia (AZ). Method A: Nine cases of hemodialysis (HD), who subsided peritoneal dialysis (PD), (including 2 DM cases:22%), Average age 75.4± 9.1 years old, 4 males, 5 females; average dialysis duration 322± 126 M:(HD-PD). B: Thirteen cases of PD, (including DM 3 cases: 23%), 6 males, 7 females; average age 71.6± 10.9 years old, average dialysis duration 286± 139 M:(PD). C: Fifteen cases of hemodialysis (HD) who was diagnosed as AZ (including 8 DM cases: 53%), Average age 76.6± 8.5 years old, 9 males, 6 females; average dialysis duration 53.9± 66.1 M:(HD-AD). We examined blood pressure (BP), and laboratory data. Analysis of the body fluid status; extracellular water/ total body water (ECW/TBW; IN BODYR), Skeletal muscle index (SMI) was performed. Average Z-score points of MRI (assessment of hippocampus atrophy evaluation) and total brain atrophy was investigated by VSRAD. Results About 13 PD and 9 HD who experienced PD cases, there were 4 MCI cases, and no Alzheimer type dementia, or cerebrovascular dementia. About PD cases, average Hasegawa’s formula expression average (HDS-R): 28.8±1.8, average BMI: 22.3± 2.9, average skeletal muscle mass index (SMI): 6.6± 1.0 kg/m2, average Lipid ratio (%): 24.3± 7.8, average Z-score points of MRI : 1.02± 0.5 and total Brain atrophy was 4.3± 2.7 %. About HD-PD cases, one case had slight cerebrovascular dementia, and 2 cases are MCI; average Z-score was 1.2± 1.0 total Brain atrophy was 3.8± 1.4 %. Average SMI: 5.9± 1.3 kg/m2, average BMI:20.7± 3.8, average Lipid ratio (%): 21.9± 8.1. Two cases died of malnutrition and sepsis. About 15 HD patients with Alzheimer type (AZ-type) dementia, average HDS-R: 10.4± 9.3, average BMI: 18.9± 2.2, average SMI: 4.7± 1.0 kg/m2, average Lipid ratio (%): 23.5± 6.1, average Z-score points of MRI: 2.6± 0.9 and total Brain atrophy was 9.3± 5.7 %. One-year survival rate of HD patients with AZ was about 20% after transferring to our hospital. The data of SMI and LP% was relatively reserved in PD and HD-PD, but significantly low from that of HD-AZ, and therefore it might not be effective in rehabilitation because of muscle weakness in HD-AZ. There were almost no HD cases with overhydration (ECW/TBW). Almost all dialysis patients had simple some old cerebral infarctions by simple CT examination. Conclusion By CT and MRI image findings, almost PD cases had old low-density area in CT and no acute cerebral infarctions in MRI. The hippocampal atrophy and total brain atrophy of PD and HD-PD was extremely mild, but was very severe in HD-AZ. There were no cases with severe cognitive impairment between PD and HD-PD even if undergoing for over ten years.