Diversifying options for income generation and employment may enhance health outcomes for women engaged in sex work. This randomized trial tested the efficacy of a microsavings intervention on reductions in economic dependence upon sex work and changes in income among women in Mongolia. Women who attended microfinance plus HIV prevention sessions reported a significantly lower percentage of income from sex work, increased odds of reporting no income from sex work, and increased odds that sex work was not their main source of income compared to women who received HIV prevention sessions alone. No significant changes in total income were observed in the treatment condition.