Summary This systematic review of population-based studies of the incidence and early (21 days to 1 month) case fatality of stroke is based on studies published from 1970 to 2008. Stroke incidence (incident strokes only) and case fatality from 21 days to 1 month post-stroke were analysed by four decades of study, two country income groups (high-income countries and low to middle income countries, in accordance with the World Bank's country classification) and, when possible, by stroke pathological type: ischaemic stroke, primary intracerebral haemorrhage, and subarachnoid haemorrhage. This Review shows a divergent, statistically significant trend in stroke incidence rates over the past four decades, with a 42% decrease in stroke incidence in high-income countries and a greater than 100% increase in stroke incidence in low to middle income countries. In 2000–08, the overall stroke incidence rates in low to middle income countries have, for the first time, exceeded the level of stroke incidence seen in high-income countries, by 20%. The time to decide whether or not stroke is an issue that should be on the governmental agenda in low to middle income countries has now passed. Now is the time for action.