A serological and medical survey on Chagas disease was carried out between December 1997 and June 2000 in four villages of the semi-arid rural Northeast Brazil. The average human serological prevalence rate of 11.8% was strongly linked with age: 1.1% for people under 25, 13.7% for people aged of 26 to 49, 29.5% for people aged of 50+. The clinical form was indeterminate for 57% of the infected population, cardiac for 35%, digestive or mixed for 8%. The infected patients under 55 received at home an etiologic treatment with benznidazol. The survey confirms the drastic reduction of Trypanosoma cruzi transmission during the last decades, especially since 25 years. This situation is the result jointly of the antivectorial activities, improvement of education level and changes in the way of life. However Chagas disease is still a serious problem, especially for numerous middle-aged infected adults. The situation could be improved by increasing the serologic screening in the field as well as the counselling and the treatment of the patients.