Incidence rates of chronic kidney disease (CKD) are found to increase with age as well as in those elderly patients undergoing renal replacement therapy. Using glomerular filtration rate as a sole predictor of CKD progression in the elderly is highly biased, unless other changes to patient health are accounted for.Aim: To determine the interrelated dependencies between chronic kidney disease with the functional status of patients aged over 65 years and to elucidate differences in functional status between CKD patients and controls.Methods: Patient subjects were qualified according to their assessed outcomes from the study protocol, which were achieved by: geriatric interview, assessing functional status by the IADL, Barthel and Tinetti tests together with assessing kidney function by performing laboratory tests of glomerular filtration rate, creatinine and urea. Subjects were divided into two groups: method 1 - according to GFR and method 2 - according to GFR and functional test results. The data were statistically analysed by structural equation modelling and k-means.Results: Positive relationships were found between the CKD stage and comorbidity (β = 0.551, p <0.0005), along with the number of medications taken and age (respectively β = 0.194, p = 0.007 and β = 0.301, p <0.0005). A highly negative relationship was observed between the CKD stage and the Tinetti test results (β = -0.716, p <0.0005), whilst more moderate ones were found with the IADL and Barthel scores (respectively β = -0.49, p <0.0005 and β = -0.402, p <0.0005). The patient groups demonstrated differences in health status when selected by method-2 for: age, comorbidity, number of medications taken, fitness test outcomes (Tinetti, Barthel and IADL tests at p <0.005). Those groups divided according to GFR, however only showed differences in age, comorbidity and the number of medication taken (p <0.005).Conclusions: The functional status worsens in geriatric patients suffering from CKD. It may thus be important to also account for disruptions to functional status when assessing CKD advancement in the elderly in addition to the GFR. The biggest problems for the over 80s suffering from CKD are gait and balance disorders, leading to a high risk of falls. Another common problem is polypharmacy, found in both the geriatric population and particularly in those suffering from CKD.