Introduction: Well‐being is an important component of health, while informal care plays a vital role in daily care of the elderly. However, the effects of informal care on the well‐being of the elderly remain unclear. This study was aimed to estimate such effects, in which well‐being was measured by 2 subjective indicators: happiness and life satisfaction. Methods: Potential endogeneity was purified using instrumental variables. Data were collected from national baseline China Health and Retirement Longitudinal Study (CHARLS).