Abstract: In most countries, labour force statistics, national accounts and censuses reflect a gross underestimation of women's participation in economic activity. The reasons for this are several. They may be ideological, in the sense that women's work is seen as secondary and subordinate to that of men, or reflect the fact that such an important part of women's work is unpaid and takes place within the household. Biases may be further reinforced by conceptual shortcomings in the categories used and/or in deficient understanding of them by data collecting agents and by respondents. Sometimes, the data collection procedures lead to deficient information. Information is usually sought with male heads of households, but in some cultures, men's and women's economies are compartmentilized in such a way that the men have little possibility of supplying reliable information about the economic activities of women. Over the last couple of decades, these problems have received increasing attention from scholars, women's organizations and various national and international agencies. (See for instance Antoine & Traore 1985, Beneria 1981, Charmes 1985, Keita 1981). But the various recommendations and guidelines which have been offered are slow in gaining acceptance, and much remains to be done with respect to making women's role more visible and realistically assessing their contribution to household survival and national production. This is particularly true ol poor women in peripheral economies.