Despite a substantial improvement incontrolling new infections of HIV over the last ten years,Mexico is experiencing a low-level epidemic withapproximately 180,000 people living with HIV (Spectrum,2013), making it the fourth ranking country in Latin Americawith regards to the number of people with the disease(PLHIV). The objective of increasing coverage and reducinginequality in the country is reflected in the objectives ofthe Specific Action Program (PAE) for the national responseto HIV, AIDS and STI of 2013-2018 (Secretaria de salud),which seeks to decrease the effect of HIV and STIs,implement prevention strategies and provide comprehensivecare for vulnerable population groups and those living inpoverty. The possibility of achieving the objectives of thePAE is closely related to the total amount of resources thatMexico can commit to fighting HIV and the way theseresources are allocated. In the hopes of assisting theGovernment of Mexico in further strengthening its HIVinvestment, the authors try to answer the question How canHIV funding be optimally allocated to the combination of HIVresponse interventions that will yield the highest impact inthe shortest period. The study found that despite theoverall greater costs of treatment with ART, this is themost cost-effective program. ART not only reduces deaths butis an effective measure to prevent new infections due to thereduction of viral load to undetectable levels. As such, themost cost-effective allocation – with no additionalresources of current Program funds, is to scale uptreatment, by about 4 to 8 percent, to maximize ART coveragewhile slightly reducing overall allocations to generalpopulation prevention.This slight increase would avert 4,235deaths and 3,371 new infections, and improve health outcomesby around 6 percent. To increase the value-for-money ofexisting resources, allocation efficiency would also requirethe strengthening of CENSIDA´s stewardship role, to ensurethat the funds transferred are invested as they wereinitially earmarked.