Background: AKI affects the outcome of different settings of critically ill patients and considered a frequent complication in them and its incidence has been increasing. Rational: AKI was defined as at least one measurement of serum creatinine of >1.5 mg/dL during the ICU stay. Objectives: to study the effect of acute kidney injury on parameters of weaning from mechanical ventilation for chronic obstructive pulmonary disease patients with respiratory failure including successfulness and duration of weaning and the length of patients stay in the respiratory care unit. Methods: the study included 50 mechanically ventilated COPD patients with respiratory failure admitted at respiratory care unit of Benha University Hospitals. The age range was between 46-80 ys. They were 43 males (86%) and 7 females (14%). Measurements and Main Results: There was significant difference in serum creatinine level after 2days and after 1week of MV in ICU among AKI cases than non AKI. On admission there is no significant difference in serum creatinine level between both groups. Conclusion: AKI is frequent in COPD patients during ICU admission. Mechanical ventilation increase risk of AKI in COPD patients.