Introduction: Acute confusional state/delirium is a frequent cause of hospital admission, in the elderly. It is characterized by an acute fluctuating impairment of cognitive functions and inattention. Recognition and prompt treatment is crucial to decrease the morbidity and mortality associated with it. Materials and Methods: In this retrospective study, we determined the etiology and prognostic factors of an acute confusional state. A total of 52 patients of acute confusional state were clinically evaluated. All patients were also subjected to a battery blood biochemical examination, cerebrospinal fluid analysis and neuroimaging. Disability was assessed by using modified Barthel index (MBI). Patients were followed-up for 3 months. Results: The mean age of our cohort was 65.04 ± 10.6 years. 32 (61.5%) patients were male. In 33 patients, we were able to identify possible precipitating cause of an acute confusional state. In the rest of the patients results of all the tests were normal. Leukocytosis and hyponatremia were frequent factors associated with delirium. The mean duration of the hospital stay was 10.73 ± 3.6 days (range 5-21 days). Patients with an abnormal work-up (possible precipitating cause) had significantly lower mortality, less duration of hospital stay and less severe disability after 3 months. Age, underlying illness, serum creatinine, abnormal neuroimaging and MBI were identified as a significant prognostic indicator. 18 (34.6%) of our patients died, of these in 10 patients we could not find a precipitating cause. Conclusion: Patients, in whom a cause was found out, had better prognosis in terms of lesser mortality and the duration of hospital stay.