Support group programmes have been proposed to alleviate the care-givers' burden and postpone institutionalisation of demented patients. Experimental studies on these programmes failed to detect any impact on care-givers' burden, but none have examined the effect on institutionalisation. The objective of this paper is to assess the impact of a support group programme for care-givers on the institutionalisation of demented patients. Forty-five care-givers of community-dwelling demented patients were allocated randomly to the study group (n = 24) and the control group (n = 21). Subjects in the study group attended a structured programme of 8 weekly sessions of 3 h each. Subjects assigned to the control group were referred to the informal monthly meetings of the Alzheimer's Society. Using survival analysis, the median length of time until institutionalisation was 30 months from the time of the entry into the study. At 24 months, the probability of being institutionalised was 0.33 in the study group and 0.45 in the control group. This difference was not statistically significant (log-rank test: chi2 = 1.02; P = 0.31). These results emphasize the lack of scientific evidence about efficacy of such programmes and the need for a large multi-centre study on this topic.