Treatment of stroke is effective when given straight away at the onset of symptoms. Our objective was to find what the present latent periods in the medical attention of stroke patients are. A study was made in 18 hospital neurology units. The time elapsed between onset of the stroke and being attended by a doctor in the Hospital Emergency Department, by a neurologist and in being admitted to hospital was determined. 794 patients were studied. The average time lapse before attention by the first doctor was 10.7 (0.1-504) hours, in receiving attention in the Emergency Department 14.1 (0.1-505), in being attended by a neurologist 24.3 (0.2-510) hours and in being admitted to hospital 21.3 (0-511) hours. In the first six hours 68.7% of the patients were seen by the first doctor, 58.2% went to the Emergency Department, 22.7% were attended by a neurologist and 22.3% were admitted to a Neurology Unit. The average time between arrival at the Emergency Department and seeing a neurologist was 10.5 (0-67.5) hours. To improve the treatment of stroke, reduction of the latent periods is necessary.