AIM To study the impact of hospital-acquired infections(HAIs)on cost and outcome from intensive care units(ICU)in India.METHODS Adult patients(>18 years)admitted over 1-year,to a 24-bed medical critical care unit in India,were enrolled prospectively.Treatment cost and outcome data were collected.This cost data was merged with HAI data collected prospectively by the Hospital Infection Control Committee.Only infections occurring during ICU stay were included.The impact of HAI on treatment cost and mortality was assessed.RESULTS The mean(±SD)age of the cohort(n=499)was 42.3±16.5 years.Acute physiology and chronic health evaluation-Ⅱscore was 13.9(95%CI:13.3-14.5);86%were ventilated.ICU and hospital length of stay were 7.8±5.5 and 13.9±10 d respectively.Hospital mortality was 27.9%.During ICU stay,76(15.3%)patients developed an infection(ventilator-associated pneumonia 50;bloodstream infection 35;urinary tract infections 3),translating to 19.7 infections/1000 ICU days.When compared with those who did not develop an infection,an infection occurring during ICU stay was associated with significantly higher treatment cost[median(inter-quartile range,IQR)INR 92893(USD 1523)(IQR 57168-140286)vs INR 180469(USD 2958)(IQR 140030-237525);P<0.001 and longer duration of ICU(6.7±4.5 d vs 13.4±7.0 d;P<0.01)and hospital stay(12.4±8.2 d vs 21.8±13.9 d;P<0.001)].However ICU acquired infections did not impact hospital mortality(31.6%vs 27.2%;P=0.49).CONCLUSION An infection acquired during ICU stay was associated with doubling of treatment cost and prolonged hospitalization but did not significantly increase mortality.