Background and Aims: Dysnatremia, a medical condition that frequently affects critically ill after admission to the Intensive Care Unit (ICUs) and is linked to a negative impact on prognosis, was the focus of this study. Other objectives were to ascertain the prevalence of hyponatremia and hypernatremia among severely ill individuals in Duhok City, Iraq, and also to evaluate their relationship with deaths and the duration of ICU stays. Materials and Methods: To accomplish the objectives of the investigation, a prospective observational study design was used. 82 patients were selected as a non-probability convenience sample. Within 24 hours of ICU admission, the critically ill were evaluated using the APACHE-II Score. All patients had their serum salt levels examined from November 2021 to February 2022, and those patients were then followed up until they knew their outcomes. Findings: Of eighty two clients, 18 (22%) had eunatremia, 26 (31.7%) developed hyponatremia, and 38 (46.3%) developed hypernatremia. 54 patients (65.9%) died. When compared to hyponatremia (53.8%) and eunatremia (38.9%), hypernatremia had the highest death rate (86.8%), and this difference was statistically significant (P = 0.0006). the significant importance of the study indicated at P-Value equal to or less than 0.05. An average score of the APACHE-II was found to be a reliable indicator of higher mortality in severely ill hypernatremic individuals. Conclusions: Compared to hyponatremia, hypernatremia showed a higher incidence and a statistically significant connection with patient mortality. The study found no association between dysnatremia and a longer duration in the intensive care unit.