The objective of this work was to find the influence of the temperatures and substrate on the germination of castor bean seeds (Ricinus communis (L.). The experiment was made according to the factorial 4x3, with temperatures of 20-35oC and 20-30oC alternated and 30oC and 25oC constat in Rolled Paper Germitest, Rolled Cotton Cloth, and Rolled Paper Germitest plus Cotton Cloth. Is was verified in these substrata that seed germination was the same using the temperature of 30oC constant. Seed germínation in temperatures of 20-35oC alternated was greater when Rolled Paper plus Cotton Cloth was used.