A multicenter retrospective study enrolled 473,482 outpatients undergoing contrast-enhanced CT with intravenous injection of nonionic iodinated contrast media (NICM) to evaluate the incidence of adverse drug reactions (ADRs) and potential risk factors. The study examined the potential ADRs of the following NICM: iopamidol (370 mg I/mL), ioversol (350 mg I/mL), iodixanol (320 mg I/mL), iomeprol (400 mg I/mL), iohexol (350 mg I/mL), iobitridol (350 mg I/mL), and iopromide (370 mg I/mL). The most commonly used NICM was iomeprol 400 (n=110,241), followed by iodixanol 320 (n=106,152). The incidence of ADRs among the included outpatients was about 0.11%; iopromide was associated with the highest risk of ADRs, while summer and autumn were acknowledged as the most relevant risk factors, being associated with the highest number of acute ADRs to NICM. Overall, this study showed that, in outpatient settings, where continuous patient observation is not feasible, NICM are safe and have a low incidence of ADRs.