Background/Objectives: The aim of the study was to compare the amount of body fat measured by skinfold thickness (SFT) and bioimpedance spectroscopy (BIS) with dual-energy x-ray absorptiometry (DXA) as a reference method. Methods: Forty-eight patients undergoing hemodialysis treatment thrice-weekly for at least 3 months (HD group) with a mean age of 59.8 ± 15.5 years, 61 patients with chronic kidney disease (CKD) with an estimated glomerular filtration rate (eGFR) <30 mL/min/1.73 m2 and a mean age of 60.1 ± 17.7 years (predialysis group, PreD), and 33 individuals without kidney disease with an eGFR >60 mL/min/1.73 m2 and a mean age of 58.7 ± 17.0 years (control group) were included. Results: Mean percentages of body fat measured by SFT did not significantly differ from those measured by DXA in the HD group (P = .249) and the PreD group (P = .355). In the control group, mean percentage of fat mass measured by SFT was significantly higher than measured by DXA (P = .004). Mean difference was 1.99% ± 3.65%. The measurements of body fat performed by BIS were significantly higher than those performed by DXA in all studied groups (P < .001). Age was statistically significant and the strongest factor that influenced the variability of measurements obtained by BIS and DXA in all studied groups (R2 = 0.302, 0.153, and 0.250, respectively, for HD, PreD, and control groups). Conclusions: SFT as a method of fat mass assessment in daily routine practice seems to be more reliable then BIS in patients treated with hemodialysis and in patients with stage IV/V CKD. However, methods based on bioimpedance techniques can potentially offer more data such as overhydration or an amount of lean tissue mass, but further investigations are needed to establish method the most suitable for patients with CKD.