objective. to analyze the challenges and accomplishments of the mexican health system as it faced the hiv/aids epidemic over the 20 years since discovery of the virus. methods. a review of the relevant literature was done. the topics revised were: hiv/aids epidemiology, the early response of the health system and civil society, prevention and risk behaviors, care and treatment, and financing and resources allocation. discussion. in mexico a rapid initial public response surely contributed to containing any early spread of the epidemic to select populations; whether that spread will continue to be contained is an open question. sexual risk practices remain high not only among traditional risk populations but also among youth. even though the epidemic remains concentrated in mexico, principally among msm and idu, only 13% of public hiv prevention funds are directed to key populations at especially high risk of becoming infected or infecting others. in recent years antirretroviral coverage has increased rapidly with funding increasing from 30 to 367 million pesos from 2001 to 2003 and coverage now approaching 100%. of all health spending on hiv/aids in the public sector, 82.4% is spent by the social security institutes and 17.6% by the ministry of health. the former provides medical care to about half of plha while the latter, in addition to caring for the other half, supports the large majority of prevention expenses. one of the challenges faced by the health system which has largely achieved universal antiretroviral coverage is how to provide quality care with appropriate monitoring, promotion of adherence and recognition and treatment of resistance and adverse effects - without dramatically increasing costs.