to evaluate the impact of a programme based on soft home care services and an offer of social caretaking, compared to one based only on soft home care, for the prevention of heat-related health events among clinically and/or functionally frail elderly. cluster randomised controlled trial. the study population included 2,612 persons over 75 years of age living alone in the city of Turin, North-West Italy, who were classified as clinically (hospitalization with specific diagnoses before summer 2004) and/or functionally (were receiving a disability pension) frail. a programme' s impact was evaluated on the basis of the hospitalizations and deaths that occurred during summer 2004, using gender-specific multilevel logistic regression models, controlling first for age and then also for education and income. among males, a weak protection against emergency hospitalization was observed within the group randomised to soft home care services and offer of social caretaking, compared to the only soft home care group (OR=0.33, 95% CI=0.11; 0.96). Among females, the programme including social caretaking seemed to lower the overall risk of hospitalization (OR=0.96, 95% CI=0.93; 0.98). this study has two important public health implications: first, it highlights the potential impact of programmes based on both soft home care and offer of social caretaking; second, it helps to raise awareness, both among health/social work and in the community, of the need for protection during summer periods for the elderly.