Background: New-onset atrial fibrillation (NOAF) is a major clinical issue for hospitalized patients, linked to clinical outcomes. This study aimed to investigate the clinical characteristics, management strategies, and outcomes of hospitalized patients with NOAF. Materials and method: This prospective, cross-sectional study included 100 hospitalized patients who developed NOAF during their hospital stay between June 2019 and May 2021. Demographic data, risk factors, clinical parameters, and management strategies were documented. Patients were followed up for one year with the primary endpoints being all-cause mortality and stroke. Results: The mean age of patients was 57.38 years with male predominance (66%). Hypertension (70%) was the most common contributing risk factor, followed by type 2 diabetes mellitus (47%). Among immediate risk factors, pneumonia (65%) and respiratory failure (57%) were prevalent. Paroxysmal AF was the predominant type (82%). Risk stratification revealed that 64% of patients had a CHA₂DS₂-VASc score >2. Electrolyte abnormalities were observed, with hyperkalemia being the most common (7%). During hospitalization, 64% of patients experienced prolonged hospital stays, and the in-hospital mortality rate was 37%. For management, intravenous amiodarone was the most commonly used antiarrhythmic agent (86.02%), while 80% received anticoagulation during the acute phase. Conclusion: The NOAF in hospitalized patients is associated with substantial morbidity and mortality. Most patients present with high CHA₂DS₂-VASc scores, indicating significant stroke risk requiring appropriate thromboprophylaxis. While intravenous amiodarone was the primary acute management strategy, the optimal approach to rhythm control and anticoagulation remains challenging in this complex patient population.