The paper reports data collected during the first three years (1983-1985) of the MONICA Project--Monitoring of Cardiovascular Diseases--in the Area Latina. The age adjusted attack rates for coronary heart disease, averaged over a three year period, were 328 per 100,000 per year in males and 101 in females. The correspondent rates for cerebrovascular diseases were 247 and 161 per 100,000 respectively. The fatality rates for coronary events were 8.3% for males and 8.6% for females within the first hour. They rose to around 30% for both sexes within 24 hours and to 56% in males and 73% in females within 28 days. The fatality rates for cerebrovascular diseases during the first day were 25.3% in males and 27.8% in females, while within 28 days they reached 44.2% and 51.0% respectively. A large proportion of fatal events (about 50% for coronary cases and almost one third for cerebrovascular cases) occurred at home without any health care assistance.