As the paradigm for IBD management is evolving from symptom control to the more ambitious goal of complete deep remission, the concept of personalized medicine, as a mean to deliver individualized treatment with the best effectiveness and safety profile, is becoming paramount. Therapeutic drug monitoring (TDM) is an essential part of personalized medicine wherein serum drug concentrations are used to guide drug dosing on an individual basis. The concept of TDM has been introduced in the field of IBD along with thiopurines, over a decade ago, and evolved around anti-TNFs therapies. In the era of biologics, TDM entered the clinical field to assist clinicians managing anti-TNF failure and its role is now moving toward the concept of "proactive" TDM with the goal to optimize drug exposure and prevent loss of response. Research in TDM is rapidly expanding: while the role of TDM with new biologics is under investigation, preliminary data suggest that software-systems support tools could be an opportunity to guide dosing choices and maximize the cost-benefit profile of therapies in the near future. The review discusses the current knowledge that poses the rationale for the use of TDM and the present and future role of TDM-based approaches in the management of pediatric IBD.