Background: This paper seeks to understand and conceptualize the experience of mothers of adolescents with intellectual disabilities (IDs) at a time in their lives which others have characterized as 'midlife' or the 'middle years of parenting'. The concerns of the paper are the lifecourse concerns in mothers' own lives and with biographical elements of becoming and being such a parent. Methods: Qualitative interviews were conducted with mothers of adolescents with IDs. The average age of mothers was 48 years. Typically parents were interviewed on two to three occasions. Results: The data suggest that despite the difficulties they faced, these parents had constructed a 'life-as-ordinary' in the early phase of their parental careers. They saw themselves as 'ordinary mothers'. However, the social content and events of the middle years of parenting prompt a realization that their lives and, for some, their sense of 'self', are undergoing considerable change. Mothers are forced to look over their lives to find the meaning and significance of these events. For some, there is biographical reinforcement. For others, there is only disruption. Discussion: The overall picture of these years is one of considerable changes and challenges, and underlines the need for a focus on the lifecourse concerns of parents as well as their children. The implications of the data for further research and service development are discussed in the context of identity theory.