The jasmonic acid is a new plant growth regulator whose application can inhibit or advance morphological and physiological changes. However its role on the seed germination is almost unknown. Therefore the objective of this study was to determine the effect of jasmonic acid and its combination with plant growth regulators in the seeds germination and dormancy break process. Seeds of lettuce (Lactuca sativa L.) ?Grand Rapid TBR? variety were submitted to different doses of jasmonic acid (0.1; 1,0; 10 e 100µM) in the presence or absence of gibberellic acid (5µM), kinetin (0,05µM) and abscisic acid (0,04µM). The seeds were placed to germinate in a germination chamber, in the dark, at 25°C and after seven days were considered germinated the ones which emitted radicle. Although the results showed that jasmonic acid has not effect on germination and dormancy break of lettuce seeds. The gibberellic acid was the plant growth regulator which isolated, promote maximum germination.