The profile of the acutely ill child and family has undergone dramatic changes in recent years Advances in medical technology have substantially altered the life-death trajectory for ill children and their families, however, they have also left families to endure increasingly difficult situations with uncertain outcomes for prolonged periods of time Nurses are interested in understanding how families manage in the face of serious illness, yet a review of the literature has revealed little progress in this area While the importance of the family has been repeatedly documented, theoretical developments regarding family process during acute illness have been limited This paper analyses those factors that have limited nursing knowledge development and, as a result, contributed to gaps in current thinking regarding the acutely ill child They include (a) a history of theoretical nursing models which, until recently, focused on the individual, (b) research that has focused on the individual parent or child while virtually ignoring family variables, (c) an outdated definition of acute illness which does not reflect the current population of hospitalized children, (d) limited use of theoretical frameworks borrowed from other disciplines, and (e) unresolved methodological issues related to the study of families in nursing