As other developing countries, the industrial development in Taiwan seems to marginalize female workers. This study tried to examine the trend of women's employment status, using both macro~ and micro~level data. The statistics suggests that female employment had significantly declined during the early stages of industrialization. Although the rapid economic development has expanded women's job opportunities, most women concentrated in lower-status jobs and informal sector. Informal employment is especially prevalent among married women. On the micro-level analysis the study examined the factors which led to the marginalization of women's labor force. The empirical analysis applied a multinomial logistic model on 1980 KAP survey sample of 3859 married women. The results suggested that married women's work patterns in terms of formal vs. informal employment are determined by the family organization rather than labor market conditions. Wives from families with small business are more likely to be involved in informal employment. Wives also tend to work informally when they have young children. On the other hand, the effects of labor market conditions are mediated by the types of family economy. Therefore the women's informal employment in Taiwan, as a characteristic of female marginalization, is the result of the sexual division of labor in the family organization and the prevalence of the family business, rather than that of being excluded into the marginal forms of employment throught the process of capitalistic production, as argued by the female marginalization theorists.