We aimed to study the epidemiology and outcome of acute kidney injury (AKI). This is a prospective study of adults aged 18 years or above diagnosed with AKI over a period of 16 months at a tertiary care hospital. Three hundred and nine patients had AKI. The observed incidence of AKI was eight per 1000 admissions. About 92.2% had community-acquired AKI (CA-AKI), and in 7.8% it was hospital-acquired AKI (HA-AKI). Etiological factors for AKI were medical in 87.4% of the cases, surgical in 9.4%, and obstetric 3.2%. Sepsis was the most common (53.1%) etiology of AKI among the medical cases. Among sepsis, scrub typhus, urosepsis, and pneumonia were the most common causes of AKI. Hypovolemia (9.4%), biological toxins (8.4%), nephrotoxic drugs and chemicals (7.4%), cardiac causes (7.4%), and acute glomerulonephritis (1.9%) were other medical causes of AKI. Nearly 38.2% had multiorgan failure, 20.1% required vasopressors, 6.1% required Intensive Care Unit support, and 23.3% required dialysis. Mortality was 8.7%. Anemia, use of vasopressor drugs, and need for intensive care support were independent predictive factors for mortality. AKI is common in hospitalized adults in India and leads to significant in-hospital mortality. AKI is largely a CA-AKI and the lesser percentage is due to HA-AKI. Many causes are potentially preventable. Early fluid resuscitation, effective anti-infective treatment, appropriate antidotes, and timely referral of established AKI patients to centers with dialysis facilities can improve AKI outcomes.