AbstractThe development and longevity of Amblyomma triguttatum triguttatum Koch were studied at temperatures of 15, 20, 25, 30, 35 and 40°C, and humidities with water staturation deficits of 2–3, 8–9 and 16–17 mm Hg. No stage developed at 40°C and the engorged larva was the only stage able to develop at 15°C. The rate of development was inversely related to temperature, with the exception of the pre-oviposition period of the engorged female which was longer at 35°C than at 30°C. The egg was the most vulnerable stage to high saturation deficit (low humidity) but some did survive in constant conditions of 16–17 mm Hg, showing an adaptation to harsh environments; A. t. triguttatum survives in a semi-desert habitat. The longevity of the unfed stages increased from the larvae, nymphs to adults. The longevity decreased with increase of temperature and decrease of humidity with the exception of adults maintained at 30°C and 16–17 mm Hg, which had a longer viability to the same saturation deficit at 20°C (50% mortality) and 25°C (50% and 100% mortality).