A comparison was made between the years 1980 and 1990 for the frequency and causes of sudden death occurring in the urban and rural areas of the city of Uberaba in individuals older than 15 years. It aims mainly to analyse the current frequency of sudden death in that region and to evaluate the impact, it any, of prophylaxis and therapy on sudden death due to Chagas' disease. For the 1226 deaths cases studied from our 1980, 54 (4.4%) were sudden ones; out of these, 13 (24.1%) were supposedly due to Chagas' disease. For the 1740 death cases studied form our 1990 series, 44 (2.5%) were sudden ones; out of these, only 3 (6.8%) were considered to be due to Chagas' disease. The results indicate a significant decrease in the frequency both for sudden death in general and for sudden death due to Chagas' disease when the year 1990 is compared with 1980. Probable explanations for the findings are discussed.