OBJECTIVE: To determine the prevalence of eight neurological problems-migraine, cerebrovascular disease, Parkinson's disease, peripheral neuropathy, disorders of neurological development, epilepsy, dementia, and sequelae of head trauma-in Colombia as a part of the National Neuroepidemiological Study (EPINEURO). METHODS: A cross-sectional survey was carried out in two phases between September 1995 and August 1996. In the first phase persons who might be suffering from a neurological disease were identified, and in the second phase a specific diagnosis was made. A sample of 8 910 people were examined, distributed in proportion to the population in each of the five geographical areas of Colombia (central, southwest, northwest, eastern, and Caribbean coast). The evaluation was done using a modified version of the neuroepidemiology protocol of the World Health Organization, along with a simplified physical examination. With the patients with possible dementia a neuropsychological examination designed for this study was used in order to thoroughly examine the cognitive aspects analyzed in the initial mental screening. The scales of Hachinski, Yesavage, and Blessed and the diagnostic criteria of the NINCDS-ADRDA were used for Alzheimer's disease; the NINDS-AIREN criteria for dementia of vascular origin; and the DSM-IV criteria for all types of dementia. A survey was conducted in order to determine if there were sequelae of head trauma. Persons 12 years old or older were evaluated by an adult neurologist and those under 12 years old by a pediatric neurologist. The prevalences of neurological disorders were calculated by age and sex, for each region and also for the entire country, with 95% confidence intervals (CIs). RESULTS: The prevalence per 1 000 population for the disorders investigated was: migraine, 71.2 (95% CI: 65.5 to 76.8); disorders of neurological development, 46.1 (95% CI: 35.5 to 58.9); cerebrovascular disease, 19.9 (95% CI: 14.3 to 27.4); dementia, 13.1 (95% CI: 8.5 to 19.3); epilepsy, 10.3 (95% CI: 8.5 to 13.0); peripheral neuropathy, 8.5 (95% CI: 6.8 to 10.7); sequelae of head trauma, 6.4 (95% CI: 5.0 to 7.8); and Parkinson's disease, 4.7 (95% CI: 2.2 to 8.9). In all those cases except head trauma the prevalence was higher among women than among men. CONCLUSIONS: These results make it possible to design more up-to-date health policies aimed at achieving more effective prevention, better control, and more adequate treatment of neurological disorders in Colombia. The easy application of these surveys and the low cost of this type of research make this methodology ideal for countries with shortages of specialized personnel.