OBJECTIVES: Infertility affects 14% of couples in reproductive age in Spain.  Progressive population ageing leads the assessment of policies that favor birthrates. The objective is estimating the lifetime economic benefits of publicly financing assisted reproductive therapies (ART) in Spain, by calculating the return on this investment. METHODS: Generational accounting model that simulates the flow of taxes paid by the individual minus those direct government transfers received (e.g. healthcare, education, pensions) over the lifecycle of a child. The cost of ART was calculated as the average cost of conceiving a child through currently available ART in Spain. The difference between discounted transfers and taxes minus the cost of ART equals the net present value (NPV) of a child conceived by ART. Year 2006 was set as the base case because of its macroeconomic stability. A 3.5% discount rate was applied. Sensitivity analysis tested robustness of results under different scenarios. RESULTS: An ART-conceived child would contribute €534,624 in net taxes to the government and would receive €479,952 in governmental transfers over her lifecycle. After discounting the cost of ART (9,000€) the NPV is estimated at €45,672. Each Euro invested in subsidizing ART reverts into fiscal benefits of €5. Sensitivity analysis shows that even in extreme macroeconomic scenarios, the long-run NPV of an ART-conceived child ranges between €11,233 and €62,470. The return on investment varies between €1.25 y €6.94 € for each Euro invested in ART. The break-even age at which the financial position begins to be favorable to the Spanish Treasury was set at 34-42 years. CONCLUSIONS: Generational accounting models allow estimating long-term fiscal implications of public funding of ART. Each Euro invested in subsidizing ART reverts into fiscal benefits of €5. Thus, investment in ART leads to substantial discounted future fiscal revenue for the Spanish Treasury, notwithstanding its beneficial psychological effect for infertile couples.