Background: Electrolyte disturbance is common in critically ill patients and it is independentlyrnassociated with increased short-term and long-term morbidity and mortality. rnObjectives: The main objective of this study was to assess the prevalence, associated factors andrnoutcome of dysnatrmia and dyskalemia in the ICUs of BLH, St peter's and Yekatit 12 hospitals. rnMethods: This was a prospective, hospital-based cohort study of critically ill patients admitted tornthe ICUs of BLH, St peter's and Yekatit12 hospital between May 1, 2021 and August 31, 2021.rnA structured questionnaire was used to collect information on sociodemographic characteristics,rnclinical profile at admission, and outcomes at discharge. Trained physician data clerks collectedrnthe data from the chart, interview and electronic medical records. Data was entered into EpiInforn3.1 and was exported to SPSS version 25 for analysis. To identify determinants of dysnatremiarnand dyskalemia, bivariable and multivariable binary logistic regression analyses were done.rnStatistical significance was considered at the level of significance of 5%, and adjusted odds ratiorn(AOR) with 95% confidence interval (CI) was used to present the estimates of the strength of thernassociation. rnResult: A total of 157 patients included in the study. The majority (64.2%) of study participantsrnare from St. Peter. More than one-third (38.4%) of them were in the age group of 31-50 years.rnThe frequency of hyponatremia was 49.68% while Hypernatremia has been found in 25.48% ofrnICU admitted patients. The magnitude of hypo and hyperkalemia is found out to be 39.49% andrn24.2% respectively. A total of 70.06% of patients were dysnatremic while 61.15% wererndyskalemic.The odds of hyponatremia increase 4.53 times with admission diagnosis of endocrinernthan non-endocrine admissions [AOR=4.53; 95% CI: 1.64 - 12.53], Similarly the odds ofrnhyponatremia increased 3.95 times with those taking beta blockers [AOR= 3.95; 95% CI: 1.43 -rn10.97].hypernatremia increased 3.17 times in those who took sedatives as compared to those whorndidnâ€™t [AOR=3.17; 95% CI: 1.28- 7.86] and in those with diagnosis of AKI in their hospitalrnstay.a single unit increase on the mean chloride increased the odds of hypernatremia by1.16rntimes [AOR=1.16; 95% CI: 1.08- 1.24].Those with admission diagnosis of COVID 19 were 75% less risk of developing hypokalemia than those with non-covid admissions [AOR=0.25; 95% CI:rn0.11- 0.61].Those with use of beta blockers were 95% less risk of developing hyperkalemia asrncompared to those who donâ€™t use betablockers [AOR=0.05; 95% CI: 0.01-0.48]. one unitrnincrease in the mean urea increases the risk of hyperkalemia by 1.02 times [AOR=1.02; 95% CI:rn1.01- 1.03]. Hypernatremia increased the risk of death 2.73 times among patients in the ICU thanrnthose with no hypernatremia. [AOR=2.73; 95% CI: 1.28- 5.85]. similarly, those patients in thernICU with hyperkalemia were 2.43 times more at risk to die than those with no hyperkalemia.rn[AOR=2.43; 95% CI: 1.13- 5.25]. rnConclusion: This study demonstrated that dysnatrmia and dyskalemia are frequent findings inrnthe critically ill. There are different determinant factors for the development of dysnatremia andrndyskalemia in the ICU. Critically ill patients with hypernatremia and hyperkalemia had a higherrnincidence of thirty-day ICU mortality.