This thesis focused on the psychological impact and parental experience of caring for a child with an inherited metabolic disorder. Due to treatment advances and early identification, many children diagnosed with inherited metabolic disorders have a favourable prognosis as treatment can prevent many of the most severe consequences. This outcome, however, requires significant input from parents to prevent associated neurological and physical impairment by adhering to strict management regimes. Research has indicated that this is likely to have a psychological impact on parents, but little is known about the further impact on parenting. Paper 1 provides a comprehensive literature review on the available evidence regarding the psychological impact on parents of caring for a child with an inherited metabolic disorder. Findings indicated that the diagnosis had a lasting psychological impact on parents, although in most cases this is not clinically significant. Ongoing psychological impact varied by the mode of diagnosis, severity of the disorder and perceived care burden. Included studies reported that parents who reported a more significant psychological impact were more likely to show greater levels of concern about their child’s disorder and use less adaptive parenting strategies. Implications for health care professionals working with parents are discussed. Paper 2 provides an interpretative phenomenological analysis of the experience of parents caring for a child with a specific inherited metabolic disorder, phenylketonuria (PKU). Seven parents of children with PKU were interviewed about their experiences of parenting their child. Three main themes emerged: control, striving for normality and acceptance as a continuum. Links between the themes were explored to outline a process that parents move through and key implications for clinical practice are identified. Paper 3 provides a critical reflection of the research process and examines the strengths and limitations of both papers.