This experiment was carried out al laboratory conditions at the College of Agriculture ?Campus? of Jaboticabal, São Paulo State (UNESP), with the objective of evaluating the performance of sunflower seeds cv. ?Anhandy? submitted to the accelerated aging test. The exposure times of the seed in the chamber were: 0, 12, 24, 36, 48, 60, 72, 74 and 96 hours, when the temperature and the relative humidity were 42oC and 100% respectively. Four replications of 50 seeds per treatment were used in a completely randomized experimental design. Afterwards seeds were submitted to a germination test at 25oC, using sterilized sand as substrate. The germination percentage was evaluated at the 7th day of testing. It was observed that the germination percentage decreased rapidly, being inversely proportional to the exposure time in the aging chamber after 48 hours. According to the obtained data 48 hours at 42oC and 100% RH would be the adequate conditions for the accelerated aging test on sunflower seed, because this is the point which is dose to the inflexion point of the polinomial curve representative of the germination.