Education and occupation as sociodemographic risk factors for dementias of the Alzheimer (DAT) and ischemic vascular types (IVD) were evaluated by two case series studies. Cases were compared to well-evaluated individuals identified as healthy normals acting as controls. There were 150 patients with probable DAT, 102 patients with probable IVD, and 188 neurologically and cognitively normal subjects. Logistic regression indicated that for DAT, education with occupation was the best predictor (OR, 1.51; 95% CI, 1.23-1.87). For IVD, the two predictors were: education with occupation (OR, 1.84; 95% CI 1.38-4.50) and education with gender (OR, 3.40; 95% CI, 1.29-8.92). We conclude that risk of dementia is increased in those with limited educational background and occupational achievement.