A survey of the district of Bambuí, Minas Gerais, Brasil, has been made in relation to the density of the tritomids and the indexes of infection fo the S. cruzi after an experimental erradicational campaign made by DIAS in 1956. A total of 332 dwellings was examined (in four localities chosen at random), 59 focuses having been found (14.76%): 15,3% of these had been already detected by DIAS in the third phase of his experimental campaign, (revision phase) six years ago, and were considered "residual focuses". The P. megistus focuses (68%) were predominant over the T. infestans (28%) and there was an association of the 2 species in 4%. The great majority of the focuses (72.9%) occurred in the interior of brick houses ("Térreos"). Only 27,10% of the focuses were found in the poor houses of straw roof. Wild focuses were not found. It must be stressed the occurence of three acute cases of the disease that were registered this year at the "Pôsto do Instituto Oswaldo Cruz" of Bambuí, the first ones to appear after the 1956-campaign; also the great acceptance of the Population to the work done, thus demonstrating the great importance of the Sanitary Education which has been given to the district for many years. Concluding: Althoug the work done by DIAS in 1956 did not completely erradicate the triatomids from the district, it was efficient for 6 years even though the campaign was not thoroughtly performed (the third phase of inspection and control was not completed). The re-infestation of the district is due to: 1) Residual focuses not detecte. 2) Residual focuses erradicated (15%). 3) Re-infestation due to surrounding districts. 4) Technical omissions during the desinsectization. Other studies will complement the present work, stressing other factors that limited the pioneer work of E. DIAS. Only then, an affirmation over the failure or the sucess of a method, may be made.