This review provides an overview and definition of the concept of neurobehavior in human development. Two neurobehavioral assessments used by the authors in current fetal and infant research are discussed: the NICU Network Neurobehavioral Assessment Scale and the Fetal Neurobehavior Coding System. This review will present how the two assessments attempt to measure similar processes from pre to post-natal life by examining three main components of neurobehavior: neurological, behavioral and stress/reactivity measures. Assessment descriptions, strengths and weaknesses, as well as cautions and limitations are provided. © 2005 Wiley-Liss, Inc. MRDD Research Reviews 2005;11:14–20.