Background/objective: although informal caregivers (ICG) find caring for a relative mainly satisfying, it can be difficult at times and it can lead to a state of subjective burden characterised by -among others- fatigue and stress. The objective of this study is to analyse the relationship between perceived social support and subjective burden in providing informal care to frail older people. Methods: a descriptive cross-sectional study was conducted using data from a large nationwide longitudinal effectiveness study.