Pediatricians play a leading role in the detection, diagnosis, and management of children with global developmental delay (GDD) and mental retardation (MR). Assessment, investigation, and consultation with the family are the prime responsibility of the developmental pediatrician, in collaboration with a multidisciplinary team. The model used by the developmental pediatrician depends on the community health framework. Significant progress has been recently achieved in identifying underlying etiologies, using a variety of laboratory tests including neuroimaging and genetic and metabolic investigations. Although being used to achieve an acceptable yield, this progress in diagnostic investigations should be associated with proper weighing of the value of each test to the diagnostic process. Optimal utilization of this rapidly expanding knowledge can only be accomplished in the setting of in-depth clinical evaluation, including a thoughtful assessment of the child and family needs. In this article, the literature on the process of clinical evaluation and laboratory work-up of the child with GDD/MR is reviewed, with an emphasis on a multidisciplinary team approach to the child and family needs. An integrated model used by the developmental pediatrician that relates to the process of evaluation and management as well as the consequences of the diagnosis on the child, his/her family, and the community is suggested. © 2013 Wiley Periodicals, Inc. Dev Disabil Res Rev 2011;17:85–92.