The experiment aimed to verify if seeds of cotton of variety FiberMax FM 993, irradiated with the doses of 0 (test); 25; 50; 75; 100 Gy can induce the production increase in cotton culture. For all treatments with irradiation, was used a source of cobalt-60, type Gammacell 220. After the irradiation, the seeds were planted in the experimental field of the Department of Plant Production ESALQ-USP, Piracicaba-SP. The experimental design was randomized blocks with four replications and 60 g of seed were used for each repetition, the rows were 5m and the spacing of 0.90m, using randomized blocks and rows of edging. After planting the final height and productivity were evaluated. The obtained data were statistically analyzed in the Tukey test at 5% level of probability. From the results obtained, it was concluded that the dose of 50Gy was the one that induced a greater production of cotton.