The literature examining the development of theoretical models of Chronic Sorrow and Parenting Stress is reviewed. A critique of these models is presented in the context of parents of children with disabilities, in the form of Down syndrome (a congenital disorder), autism (a pervasive developmental disorder) and acquired brain injuries (through trauma, infection or ischaemic event). These three diagnostic categories represent time specific onsets with Down syndrome recognised in utero or at birth, autism typically manifesting at two to three years and brain injuries being acquired at any point in a child's development. This study examined how the temporal aspects of onset of disability may be significant in the development of Chronic Sorrow and consequential Parenting Stress. Measures of stress, sorrow and adaptive behaviour were administered to parents of children in all three diagnostic categories. Results indicate significant effects on stress and sorrow of the age of the child when parents first suspected a problem, parental education and occupation, the gender of both parent and child and satisfaction with informal support levels. A strong relationship between stress and sorrow even when controlling for adaptive behaviour was found, thereby identifying areas for future research into the implications of these findings for clinical practice.