Broccoli is a functional food and can accumulate selenium. However, biofortification with selenium may alter the profile and amount of bioactive compounds, such as sulforaphane. In this sense, this abstract aimed to evaluate the influence of selenium treatment on sulforaphane in broccoli seedlings. After 15 days of germination, broccoli seedlings were randomly separated and treated with 2 mL of distilled water (MS) or 50 µM sodium selenate solution (MC) during more 15 days. In the 30th day after sowing, broccoli seedlings were collected, the roots were removed and the leaves were stored in plastic bags. The sulforaphane was extracted with dichloromethane for 1 hour at room temperature, evaporated to dryness in a vacuum at 45 ºC, and redissolved in 2 mL of acetonitrile. A 20 μL-aliquot was injected into an HPLC system (Shimadzu 20A). The analysis was carried out isocratically at a flow rate of 0.6 mL/min, employing acetonitrile:ultrapure water (30:70, v/v) as the mobile phase. The Waters Spherisorb® column (ODS-C18) was thermostated at 36 °C. The measurement was carried out at 254 nm and the total time between injections was 20 min., with the results expressed in µg sulforaphane 100 g/fresh weight (FW). The difference between the means of the treatments with and without selenium was tested using a Student’s t-test. The sulforaphane content was higher in MC (7686.79±305.60 µg/100 FW) compared to the MS (6890.17±396.72 µg/100 FW). This increase may be related to an increase in the myrosinase activity. Moreover, biofortification with Se can exert an additional effect on the synthesis of proteins and amino acid (methionine, phenylalanine, tyrosine and tryptophan). Therefore, the variation in these amino acids and synthesis of these amino acids may influence the production of these compounds. In conclusion, the treatment with selenium significantly increased the content of sulforaphane in broccoli seedlings.