Using data from the 1986 Income Distribution Survey and other sources, a comparison of the socio-economic status and employment patterns of single mothers and married mothers is presented. A model is then developed and estimated using a probit analysis of factors thought to explain employment status (employed full-time, employed part-time, not employed) and the relative importance of marital status in determining employment status. Factors included in the model are the woman's age, her level of educational attainment. her previous employment experience, age(s) and number of dependent children, access to non-earnings forms of income, and, for married mothers, the employment status of her spouse and his income. The results indicate that most of the variation in labour force behaviour of the two groups can be explained by variations in the factors listed above. However, even after adjusting for all other factors, it is still true that sole mothers are less likely than married mothers to be in the labour force, but if they are employed they are more likely (than married mothers) to be in full-time employment The major differences between the two sets of mothers is in their responsiveness to changes in their access to sources of income other than earnings.