Purpose: This review provides a focused and comprehensive update on emerging evidence related to acute kidney injury (AKI). Principal findings: Acute kidney injury is a significant clinical problem that increasingly complicates the course of hospitalization and portends worse clinical outcome for sick hospitalized patients. The recent introduction of consensus criteria for the diagnosis of AKI (i.e., RIFLE/AKIN classification) have greatly improved our capacity not only to standardize the diagnosis and classification of severity of AKI, but also to facilitate conducting comparative epidemiologic studies in an effort to better understand the burden of adult and pediatric AKI and its syndromes (i.e., septic, cardio-renal, hepato-renal). The characterization of several novel AKI-specific biomarkers (i.e., neutrophil gelatinase-associated lipocalin, kidney injury molecule-1, and interleukin-18) is extending our understanding of the pathophysiology of AKI. Moreover, these biomarkers appear to have clinical relevance for early detection and they provide prognostic value. These innovations are aiding in the design of epidemiologic surveys and randomized trials of therapeutic interventions. Strategies for prevention and conservative management of AKI across a range of clinical settings are discussed, including sepsis, hepato-renal syndrome, cardio-renal syndrome, rhabdomyolysis and in the perioperative setting. Conclusions: Acute kidney injury is an escalating clinical problem in hospitalized patients. Recent advances in AKI have improved knowledge of its pathogenesis, diagnosis, and prognosis; however, considerable research effort is needed. There are still relatively few interventions proven to alter the natural history of established AKI in hospitalized settings, and its development foretells less favourable outcomes.