Recently published data confirming dramatic survival benefits for infants started on ART as early as possible after the diagnosis of HIV, prompted a review of the World Health Organization (WHO) pediatric treatment guidelines. In June 2008, new guidance was issued, which recommends prompt initiation of ART in infants diagnosed with HIV infection. In order to identify those infants who will need immediate ART, early confirmation of HIV infection is required. In November 2008, a meeting was convened to review recommendations by WHO for the diagnostic testing of HIV infection in infants and children. The meeting brought together the guideline review group that had developed the initial recommendations in 2005 The guideline review group followed the grading of recommendations assessment, development and evaluation (GRADE) approach in reviewing the recommendations for early detection of HIV infection according to the current WHO Guidelines for Guidelines. This document contains the new recommendations.