In this work, a simple MEKC method for the determination of C and seven B-group vitamins in energy and sport beverages was developed. The influence of composition of background electrolyte (BGE) and other MEKC parameters on migration time separation of the vitamins were investigated. Also, a study with some matrix compounds commonly present in these beverages, which could interfere in vitamin determination, was performed. The performance of the developed method was tested with regard to sensitivity, limit of detection and repeatability. Finally, the vitamin content present in several energy and sport drinks and fruit nectars was obtained.