The hedonic definition of subjective well-being (SWB) includes subjective perceptions of moods and cognitive judgements of life satisfaction. Little is known about levels of well-being within families when other family members have a chronic illness. This paper explores these associations. Data come from year 1 wave 1 of Understanding Society, a new longitudinal UK-representative household panel survey. SWB of adults (³ 16 years) was measured using the GHQ-12, the Short Warwick-Edinburgh Mental Well-being Scale and a life satisfaction question. The Strengths and Difficulties Questionnaire measured well-being in youth (10 to 15 years). Self-reported long-term limiting illness (LLTI) was used to indicate chronic illness. Various models incorporating latent variable and multi-level frameworks were used to explore associations between illness and SWB between partners, between older parents and adult children and between young child and parents. LLTI in one partner was negatively associated with own and their partner’s well-being. There was a significant association between a parent’s LLTI and SDQ total difficulties score for youth. These associations were accounted for in part by caring/being cared for and the physical and mental functioning of the family member with a LLTI. Adult children and their older parents did not show any association between LLTI and SWB. The findings from this study indicate that the limiting illness of one family member has differential associations with the well-being of other family members.