Using data from the China Health and Nutrition Survey (CHNS), this study investigated the impact of informal care on female caregivers' subjective well-being in China. We found that informal care significantly reduced the subjective well-being of female caregivers using the instrumental variable (IV) ordered probit model. Our results revealed that the care effect on subjective well-being was more significant for rural caregivers than for urban caregivers. The more hours or more recipients care was provided for, the greater the negative impact on subjective well-being. Based on these findings, we further identified the two channels of 'wealth' and 'health' through which informal care lowered subjective well-being. These results have implications for policy makers in overcoming the challenges involved in constructing and developing a supportive system of informal care in China. Highlights • Informal care significantly reduced the subjective well-being of female caregivers. • Care effects on subjective well-being were more significant for rural caregivers. • The more care given, the larger the negative impact on subjective well-being. • Caregiving reduced subjective well-being through lower wealth and worse health.