The preimbibition and prechill effects were studied on the emergence and vigor of guarana seed (Paullina cupana var. sorbilis (Mart.)) Ducke. Immediately after harvesting and aril removal, the seeds were submited to following treatments: preimbibition in destilled waater during 12, 24, 36, 48, 60 and 72 hours; and prechill at 3-5 oC, during the same periods. The experiment duration was 120 days, and wereanalysed the emergence percentage, speed of emergence amd seedling height. The results showed that preimbibition and prechill did not affect the emergence and vigor of guarana seeds.