"Guaraná" seeds (Paullinia cupana var. sorbilis (mart.) Ducke) were submited to thermic pretreatments of 40oC and 50oC, combined with exposition time of 15, 30, 45, 60, 90 and 120 minutes, with the intent to obtain uniform emergency and to reduce the period to the formation of the nursey tree. Seeds were sown 2cm deep, in a substratum of tanned sawdust treated with methyl bromide. The final data of emergence percentage, epicotyl lenght, embryo dry and fresh weight, were taken 150 days after seeding. Seed exposition to 40oC during 90 minutes gave best emergence. This treatment, however, was not capable of accelerating or making uniform the terminative process. The pretreatment of seeds under the temperature of 50oC, with exposition periods of 90 and 120 minutes, killed almost all the embryos.