Introduction Approximately 24.2 million persons throughout the world suffer dementia with 4.6 million new cases reported annually. Only 10% of dementia and Alzheimer's disease studies are conducted in developing countries where 66% of sufferers live. Cuba, a developing country, exhibits health indicators similar to those of developed nations. Its population of 11.6 million is aging rapidly: by the year 2020 it is estimated that persons aged ≥65 years will comprise 25% of the population, making Cuban society the "oldest" in Latin America. Objectives Ascertain and characterize behavior of dementia, its etiologies and risk factors in persons aged ≥65 years in the Havana City municipality of Playa. Methods A two-phase, cross-sectional, door-to-door study was conducted in the municipality targeting all persons aged ≥65 years, achieving a 96.4% response rate (n=18,351). Folstein Mini Mental State Examination (MMSE), Hughes Clinical Dementia Rating (CDR) and a structured interview on risk factors were applied. DSM-IV, NINCDS-ADRDA and NINDS-AIREN criteria were used to determine dementia diagnosis, as well as other criteria for diagnosing Alzheimer's and other specific forms of dementia. Results Dementia prevalence was 8.2% of adults aged ≥65 years, with a slight predominance in males. The most frequent cause of dementia was Alzheimer's disease, followed by mixed dementias. Dementia-associated risk factors were: history of stroke, hypertension, depression, skull-brain trauma, family history of dementia, low educational level and advanced age. Conclusions This study corroborates that dementia and Alzheimer's disease constitute an important and growing health problem for our country due to the accelerated aging of the Cuban population. It also underlines the importance of early diagnosis and proper treatment of hypertension and other vascular risk factors, as well as the need for a national public health program for the prevention and early diagnosis of dementia and Alzheimer's disease, targeting elderly and at-risk populations.