Background: Relationships between child quality of life (QOL), maternal well-being and parenting were explored in a questionnaire study. Method: Mothers of 126 full-term (FT) and 91 pre-term (PT) infants during the child's second year of life completed measures of their own and the child's quality of life and behavioural difficulties. We developed a measure of parenting style derived from Regulatory Focus Theory (RFT), to distinguish greater reported use of promotion as opposed to prevention strategies (emphasising gains rather than losses, and encouraging pursuit of goals rather than prevention of harm). Results: The two groups of mothers showed no differences on the parenting measure, but those in the PT compared with the FT group described their infant as having lower QOL and more behavioural and mood problems, and rated their own well-being as less satisfactory. Greater use of promotion was associated with reports of fewer difficulties (better QOL) for the child and better mothers' well-being. Differences in mothers' well-being as a function of group (FT vs. PT) and promotion were strongly mediated by mothers' perceptions of their child's difficulties. At the same time, associations with child difficulties were partly mediated by mothers' well-being, suggesting that maternal distress may have partly contributed to higher perceptions of such difficulties. Among PT infants, the degree of prematurity predicted child difficulties, but was not consistently related to mothers' well-being. Discussion: Mothers of PT infants report more physical health and behavioural difficulties than mothers of FT infants, but specific parenting styles can contribute to child difficulties and QOL in both infants and their mothers. Conclusion: We conclude that RFT has potential for understanding the conflicts experienced by parents caring for vulnerable children.