This paper investigates the hypothesis that children work because their income contribution is necessary for the household to meet subsistence expenditures. It uses the fact that a testable implication of this hypothesis is that the wage elasticity of child labor supply is negative. Previous work has tended to infer from a negative income elasticity that poverty drives children into work. It is argued here that a negative income elasticity only tells us that child leisure (or education) is a normal good. Using a large household survey for rural Pakistan, labor supply models for boys and girls in wage work are estimated. Conditioning on full income and a range of demographic variables, the author identifies a forward falling labor supply curve for boys, consistent with the view that boys work on account of the compulsions of poverty. This is less clear in the case of girls. Therefore, while raising the return to schooling for girls may draw them out of work, eliminating boys'wage work requires alleviations of the poverty of their households. Trade sanctions or bans on child labor may have deleterious consequences for these households unless they are compensated for the loss in income.