In March 2010, the Food and Drug Administration (FDA) issued a black box warning for anti-D immunoglobulin (anti-D), an approved treatment for immune thrombocytopenia (ITP). It is unknown if and how clinical practice at U.S childrenʼs hospitals has since changed. We sought to describe inpatient anti-D usage, laboratory monitoring, and anti-D complications before and after the FDA warning. Using the Pediatric Health Information System, we collected data from 41 childrenʼs hospitals. There was a modest but statistically significant decrease in anti-D usage from pre-warning to post-warning. Severe complication rates were very low and did not change appreciably. Pediatr Blood Cancer 2013;60:E149–E151. © 2013 Wiley Periodicals, Inc.