Because of the increased use of contrast media, the potential risk of contrast-induced acute kidney injury (CIAKI) has also increased. CIAKI often results in chronic kidney disease (CKD), an affliction with increasing incidence in modern society. The current prevalence of CIAKI is difficult to estimate because most victims are asymptomatic. The first Japanese guidelines regarding contrast agent examinations were recently announced, but their only recommendation is to provide classic fluid replacement with saline 6-12 h before and after the contrast procedure. According to a review summarizing the recent literature, little evidence supports this suggestion. To obtain early diagnoses and to treat emergent patients, it is appropriate to perform procedures using contrast media without knowledge of patients' renal function. Prevention of CIAKI is the most important consideration, and the usefulness of risk scores predicting the development of CIAKI has been reported. However, no prospective studies have been performed to date, and, therefore, such studies will be necessary in the future. Furthermore, the development of novel preventative interventions for CIAKI is also required.