In the municipality of Pereiro an area where Triatoma pseudomaculata is prevalent and Triatoma brazitiensis only rarely seen, a house was selected for demolition. It was one of 13 houses of a community of 74 people. In a survey 41 T. pseudomaculata were captured only 2.4% of which were infected with Trypanosoma cruzi. Human infection in the area was 2.2% and there was a low infection rate in domestic animais (2.0%). The house to be demolished was sprayed with BHC one year previously. 20 T. pseudomaculata captured before demolition had a 50% infection rate. At demolition 6 people, 1 dog, 1 cat, 1 pig and 30 chickens were present in the house. 221 triatomids were captured at demolition,.0.5 per square metre in the roof and 1,4 per square metre in internal and external walls. 180 were examined and 7.2% were infected. We conclude that by normal methods only a small proportion of the bug population is captured in a house. The infection rate in T. pseudomaculata reveals its capacity for transmitting T. cruzi especially as 20% of the infected bugs were captured in te bedroom.