Declining fertility in both the developed and developing world has led to large and potentially welfare-enhancing changes in women’s labor supply, education and investment in children in recent decades. However, it has been widely noted that the pace of this decline has stalled even while access to contraception has continued to expand, raising the question of whether increasing access to contraception is sufficient to lead to declining fertility. This paper provides evidence about the relationship between contraceptive access and fertility from a randomized controlled trial in Lusaka, Zambia, in which women of child-bearing age were provided with a voucher for free and immediate access to long-acting forms of contraception; this voucher was provided either to the woman individually, or the woman jointly with her spouse. Results show that there is a significant increase in contraceptive use, and a particularly large increase in experimentation with new contraceptive methods, but no decline in births in the short- or long-term compared to a control group who did not receive increased access to contraceptives.