: By 1994, Health Psychology had been established as a discipline, and defined by Marie Johnston as the scientific study of the psychological processes and behaviour in health, illness and health care. Health Psychology, so far, has mainly related to the adult population, although increasing attention is now being paid to both pediatric and broadly-based child health psychology. It is noteworthy that attention devoted to pediatric and child health psychology has increased dramatically, but the great majority of published work refers to the child and not to the preterm neonate; yet being preterm means being born early, and sometimes too small, and is a stressful life event. In the field of Medicine, Neonatology has appeared as a sub-discipline, and both investigates and cares for at-risk babies, including risk for developmental disabilities. The time is consequently opportune for psychology to make an effective contribution to both the theory and care of the preterm neonate, viewed as a unique, emergent, coactional and hierarchical human being. The formal framework for this is Neonatal Health Psychology (NNHP), which is defined in the article as 'the scientific study of biopsychosocial and behavioural processes in health, illness, and health care of the preterm (and fullterm) neonate during his/her first 28 days of life, and the relationship of such processes with later outcome.' Early work in this category has shown that NNHP has profound interdisciplinary connotations, not least because of the diverse ways in which information has to be derived from the non-verbal neonates. The pathways and scope of NNHP are identified, and many examples of work with preterm neonates are summarised in the article. In making the case for the professional formalization of NNHP, descriptions are given of Neonatal Assessments and very-early interventions; the interdisciplinary character of much of the early work is shown to have been essential. Indication of theoretical frameworks for NNHP is given.