Consumption of cruciferous vegetables (Brassicaceae) has been associated with prevention of chronic non-communicable diseases. Unlike other plant species, they are able to accumulate the essential micronutrient selenium and synthesize seleno-compounds with additional health benefits. Biofortification of cruciferous vegetables could be a solution to combat selenium deficiency and a means to enhance their health-promoting properties. However, biofortification leads to alterations of plant metabolism from micro- and macronutrients to various types of phytochemicals. This systematic review presents factors controlling selenium addition has on nutrients and phytochemicals of cruciferous vegetables. Selenium compounds of Brassicaceae and their possible cancer-preventive properties are also presented. Literature research was performed using four known databases by keywords such as cruciferous vegetables names and selenium biofortification. Over 90 references, mainly from the last decade, have been reviewed. Findings suggest that selenium biofortification affects differently the contents of nutrients and phytochemicals and therefore the biofortification process for each crop should be designed accordingly taking into account selenium toxicity. [ABSTRACT FROM AUTHOR]