The blood sucking bug Triatoma rubrofasciata (Heteroptera: Reduviidae) existed In the nature long time ago. However, It has recently become epidemic diseases at some big citys Vietnam. In Vietnam, up to now, not to have the project that research on It. This that is the first pape in Vietnam is . initial research on morphological and biological characteristics of egg and nymph of blood sucking bug Triatoma rubrofasciata in the lab condition. The research results. show that eggs have length 1.65 -1.75 mm (average 1.69 +/- 0.10 mm) and wide 0.8 -1 mm (average 0.90 +/- 0.07 mm), length first instar nymph 2.4 - 2.6 mm (average 2.50 +/- 0.02 mm) and wide 0.9 - 1.1 mm (average 1.03 +/- 0.01 mm). In laboratory condition (28.55 - 30.45°C, 71.12 - 76.20 percent RH) then development time of egg were 13 - 16 days (average 14.32 +/- 0.36 days), hatch rate average 96.33 percent. The first instar nymph of tHis species (not sucking blood) will is not enough to complete development time become second instar, and lite time was 16 - 29 days. However, first instar nymph of blood sucking bug Triatoma rubrofasciata were enough sucked blood (one times) that will enough to complete development time of first instar become second instar nymph with development time was 12 - 27 days (average 15.20 +/- 0.38 days).