Information on the prevalence of dementia is rare in the Middle East, including dementia comorbidities with diabetes, ischemic heart disease (IHD), diabetes, and severe mental illnesses (SMI). This study aims to examine the 1-year prevalence of dementia and the aforementioned comorbidities in a representative national Israeli cohort aged 60 and above. The study design was a nationally representative cohort. The source sample comprised 122,829 persons aged 60 and above in 2015. The dementia group consisted of 8,153 patients (6.6%). The rate of dementia approximately doubled for every 5 years of maturation to the age of 84, and dropped thereafter. Dementia was significantly (P < 0.0001) more likely among women (N = 4,899, 7.4%) than men (N = 3,254, 5.7%). Based on multivariate logistic regression models, the group with dementia compared with the group without dementia had statistically significant (P < 0.001) lower odds of diabetes (OR = 0.78) and IHD (OR = 0.87), and significantly higher odds of SMI (OR = 4.96), accounting for age and gender. The prevalence of dementia delineated by age and gender in Israel resembles those found in other developed nations. Generally, dementia was associated with more SMI and less IHD and diabetes.