Pre-print, Working paper: For a sub-sample of French households of an Insee wealth survey, we obtain new and relative measures of 5 individual preference parameters : the risk "attitude" (aversion, prudence…), the rate of time depreciation over the life-cycle, the degree of short-term impatience, and the degrees of family and non family altruism. Short-term impatience and non family altruism are found no to affect wealth but, contrarily to recent results of behavioural analysis, the three other parameters have significant effects on wealth (financial, gross or net), which are consistent with theoretical predictions : wealth accumulation increases with the degree of prudence (precautionary saving), falls with time preference (life-cycle saving) and rises with the degree of family altruism (wealth intended for bequests). The way preferences are measured allows to get rid of potential causality problems and the joint explanatory power of the three parameters appears sizeable, although less important than the one of classic explanatory variables (age, income, social class and inheritance).