ABSTRACT Aim to analyze the relationship between family functionality and burden of informal caregivers of hospitalized older people. Methods this is a cross-sectional study conducted with 98 informal caregivers of hospitalized older people in an inpatient unit of a large hospital in São Carlos, São Paulo. For data collection were used questionnaires to sociodemographic and care context characterization, to evaluate burden and family functionality. Descriptive analyzes and Spearman’s correlation coefficient were used. Results female caregivers predominated, who took care of their parents and had no training. Approximately 59.8% of caregivers had good family functionality and 49.5% scored for mild to moderate burden. There was a negative correlation, moderate magnitude, between family functionality and burden (p<0,001). The higher the burden score, the lower the family functionality score and vice versa. Conclusion caregivers with high burden had worse family functionality. Therefore, nurses need to identify such conditions early and implement assertive interventions so that the family functions as a therapeutic resource.