The sequence of mating behaviors of Triatoma mazzottii Usinger was established under laboratory conditions. In 180 observations with 70 pairs of insects, copulation was completed on 20 occasions, females were not receptive on 50 occasions, and males were indifferent on 110 occasions. The behavior pattern consists basically of nine steps, seven by the male, one by the female, and one by both: (1) male vigilant position, (2) female advance movement, (3) jumping onto or mounting, (4) gyration, (5) dorsolateral position, (6) juxtaposition of genitalia, (7) copulation, (8) subjection of the female, and (9) separation. Copulation usually went to completion after the male had completed the gyration step. The duration of copulation was 10:55 ± 2:06 min. The possible effect on this behavior of a sex pheromone is discussed, as are other factors that may affect copulation. Inglés