The aim of this research was to study the effects of temperature on the seed germination of Leucaena leucocephala (Lam.) de Wit, Kind Peru, cv. Cunninghan. First the seeds were chemically scarified with H2SO4 during 40 minutes and after washed in distiled water. Finally, four replications of 100 seeds were distributed in Petri dishes having filter paper moistened with captan (0,2%). The temperature limits for germination were between: 10-15°C (minimum), 30-35°C (optimum) and 40-45°C (maximum). For evaluation of termal stress the seeds were exposed to different treatments: 12, 24, 48 and 72h at 50°C; 24 and 48h at 65°C; 24h at 85°C. When the seeds were dried, they remained viables after expositions up to 85°C during 24 hours. The opposit was notified for the imbibed seeds exposed at 50°C for 12 hours.