Background: Elderly caregivers present increased physical and mental health problems. These factors can lead to a lack of autonomy and a need for social support. This study aims to analyse the relationships between perceived social support and mental health status in elderly caregivers aged 65 and older. Methods: a cross-sectional study based on data from the Spanish National Health Survey (ENSE-17) carried out on 7023 people. The study population was restricted to 431 caregivers aged ≥65 years. A study of the correlation between the mental health state and the perceived social support was carried out. Both variables were related to the sex of the caregiver. Results: Perceived social support by older caregivers is significantly related to mental health (p = 0.001), and stress (p < 0.001). Also, there is a significant relationship between perceived social support and mental well-being (p = 0.001), self-esteem (p = 0.005) and stress (p = 0.001) in older women caregivers. Conclusions: Older caregivers have adequate mental well-being and perceive high social support. Perceived social support can contribute to improving the mental well-being of older caregivers.