Acute kidney injury (AKI) in patients hospitalized in the intensive care unit (ICU) results in increased morbidity, mortality, and as a consequence, higher health-care costs. The bad prognosis associated with this condition and limited health-care budgets both have raised the issue of how much therapy should be dedicated to ICU patients with AKI. As no universally-agreed standardized definition for AKI is available, wide ranges of incidence are reported and precise estimates of its associated excess of costs are, therefore, difficult to explore. Nonetheless, significantly prolonged hospital length of stay (LOS) and higher costs in ICU patients whose course was complicated with AKI are reported. Moreover, among survivors, even greater requirements of in-hospital and post-hospitalization care was noted. Notwithstanding the high health-economic burden, full supportive intensive care treatment is justified in this particular cohort of patients. Major efforts are highly required in terms of public health prevention initiatives and the early recognition and timely management of AKI, in ICU hospitalized patients in particular.