Background and objectives: Uremic encephalopathy is the most important complication of renal failure and urgent dialysis treatment is required. Parathormone (PTH) contributes to the etiopathogenesis of uremic encephalopathy. PTH is a hormone that acts in the calcium balance in the organism. The aim of our study was to investigate the effect of serum adjusted and ionized calcium on the development of uremic encephalopathy in patients with acute renal injury (acute kidney injury network (AKIN) stage 3). Materials and Methods: Our study was supported by Canakkale Onsekiz Mart University Scientific Research Projects Unit (ID:1278). Three groups were formed for the study. The first group was acute renal failure AKIN stage 3 (N: 23), the second group was AKIN stage 3, and the patients who had emergency hemodialysis (N: 17) and the third group (N: 9) had AKIN stage 3 hemodialysis due to uremic encephalopathy. In these patient groups, 25-hydroxy vitamin D, PTH, calcium, albumin, urea, creatinine, and blood-gas-ionized calcium were observed in their serum during the first application. Calcium, albumin, urea, creatinine, and ionized calcium in blood gas were also examined in serum at 24th and 72th hours. Data were analyzed using SPSS version 19.0. Kruskal-Wallis test and Mann-Whitney U test were applied for the variables that did not comply with normal distribution. p < 0.005 was accepted statistically. Results: A statistically significant difference was found between the measurement creatinine values at the 24th and 72th hours of admission in AKIN stage 3 patients who applied to the emergency department (p = 0.008). A statistically significant difference was found in the measured calcium values (p = 0.013). A statistically significant difference was found in the measured ionized calcium values (p = 0.035). Conclusions: In our study, the effect of ionized calcium level on uremic encephalopathy in serum creatinine, calcium, and blood gas in patients presenting with acute renal injury, AKIN stage 3, was significant, but studies with new and large groups are needed.