Mexico City has the highest aging rate in the country, as well as a high prevalence of diabetes mellitus (DM) and hypertension (HT). It is known that each one of these conditions increase oxidative stress (OS) independently. With this study we described changes in OS of 18 patients without DM or HT (controls), 12 with DM, 23 with HT, and 18 with DM and HT, all of them members of the COSFAMM (Cohorte de Obesidad, Sarcopenia y Fragilidad en Adultos Mayores de México). OS was measured by the quantification of reactive oxygen species (ROS), by the oxidation of diclorofluorosceine, and by determination of lipid peroxidation by product malondialdehyde (MDA). HT patients showed increased ROS levels, as did men with HT compared with the respective DM and HT groups. Also, women of control group showed higher levels of ROS compared with men. Generally, HT turned out to be the most influential factor for the increase of oxidative stress in the elderly while DM has no effect whatsoever.