Introduction Acute kidney injury (AKI) is common in patients admitted to a hospital. Various studies report the incidence of hospital acquired acute kidney injury (HAAKI) from 2–7 %. The reported mortality rate ranges from 25 % to 70 %. This study aimed to study the incidence and outcome of HAAKI in a tertiary care hospital in north India. Materials & methods This prospective single centre based hospital observational study was conducted for 18 months at a tertiary care centre. HAAKI was defined as the development of AKI any time after 24 h of hospitalization, in a patient who was admitted with normal renal function. Serum creatinine (SCr) and urine output were monitored daily and at the end of 30 days. Renal replacement therapy (RRT) was instituted according to standard clinical indications. The outcome of the patients as well as renal outcome was ascertained at 30 days after optimal management. Appropriate statistical methods were used to analyze the data. ResultsA total 8159 new patients were admitted in acute wards and ICU during the study period, out of which 102 patients were diagnosed with HAAKI with incidence of 1.25 %. Oliguria in 20 patients (19.6%)was less common than non–oliguric subset. However, they were found to have worse AKIN stage than non–oliguric patients with 15 out of 20 patients in AKIN stage 3. Mortality rates were also higher in this subset with 16 out of 20 patients having fatal outcome. Further, the patients who had oliguria were more likely to need RRT when compared to non–oliguric patients. (19 out of 20, p< 0.001). Sepsis was the most common cause accounting for 52.43% of patients with HAAKI.Complete renal recovery at 30 days was found in 42 (41.17%) patients, Partial renal recovery in 44 (43.13%) and no renal recovery in 11 (10.7%). Among the 102 patients with HAAKI, 23 required RRT (22.5%).The mortality rate for HAAKI in our study was39.21%. (40/102). ConclusionsHospital–acquired acute kidney injury is a relatively common and serious occurrence that is associated with increased mortality and resource consumption. Oliguric AKI is less common than non–oliguric AKI, but is significantly associated with increased severity of AKI, increased requirement of RRT during the course of illness and poor patient as well as renal outcome.