OBJECTIVE. The purpose of this study was to evaluate the incidence and severity of acute allergic-like reactions related to IV administration of low-osmolality nonionic iodinated contrast material in children. MATERIALS AND METHODS. Department of radiology contrast material reaction forms involving pediatric ( younger than 19 years) imaging examinations performed from January 1, 1999, through June 30, 2006, were retrospectively evaluated for type of acute allergic-like reaction, severity of reaction, and patient outcome. The electronic medical record was reviewed for pertinent medical history related to each acute reaction, including previous contrast material reaction, premedication before administration of IV iodinated contrast material, previous allergic-like reaction to substances other than contrast material, and history of asthma. RESULTS. In our department during the time period specified, 11,306 pediatric IV administrations of low-osmolality nonionic iodinated contrast material were performed. Acute allergic-like reactions to the contrast material were documented in 20 ( 0.18%) of the patients. Sixteen ( 80%) of the acute allergic-like reactions were categorized as mild, one ( 5%) as moderate, and three ( 15%) as severe. No deaths were attributed to IV nonionic iodinated contrast material. Six ( 30%) of the patients had a history of allergic-like reaction, including two patients who had a history of reaction to iodinated contrast material. Five ( 25%) of the patients had a history of asthma. CONCLUSION. Acute allergic-like reactions to IV administration of low-osmolality nonionic iodinated contrast material in children are rare. As in the adult population, most pediatric reactions are mild; however, severe reactions do occur.