Five aspects of the behaviour of the Triatominae are reviewed: hostfinding, defence from predators, habitat selection, activity patterns and substrate preferences, and mating and oviposition behaviour. It is emphasised that knowledge of behaviour is largely restricted to the three species Triatoma infestans (Klug), Rhodnius prolixus Stål and Panstrongylus megistus (Burm.) and that the behaviour of other species, particularly those with predominantly sylvatic habits, may be quite different in some respects.