Noting Congressional interest in encouraging low-income mothers to seek employment as an alternative to receiving welfare, this report describes a study of the impact of child care expenditures on mothers' decision to work and compares the differences in costs for poor, near-poor, and non-poor mothers. The study developed measures for predicted wages and child care expenditures, and separated the sample into three groups: poor, near-poor, and non-poor mothers. Data were drawn from the Urban Institute's 1990 National Child Care Survey, and the Survey's Low Income Sub-study. Analysis of findings showed that subsidizing child care costs has the greatest impact on poor and near-poor mothers' decision to work, as compared with non-poor mothers. Half of poor mothers used informal care for their children. The results suggest that child-care subsidies can make a substantial difference in the probability of poor and near-poor mothers' maintaining employment. The report's two appendices provide an economic analysis of the effect of child care subsidies on mothers' decision to work and General Accounting Office (GAO) contacts and acknowledgements. Contains 14 references. (AP)