Many significant events have occurred in the recent past that beg a broad audience to address the question "What is pediatric transfusion medicine?" Herein, we list some of these events and their relevance below and attempt to provide an answer for this question. Indeed, several issues regarding the subspecialty of pediatric transfusion medicine (PTM) are particularly timely, and it appears that a critical mass, or a nidus capable of becoming a critical mass, is developing in PTM.