Royal jelly (RJ) is a bee product with great potential as a supplementary food and in the future it will be very important for the pharmaceutical industry. The aim of this study is first to determine the content of 10-HDA in Bulgarian RJ and second to identify if the content of 10-HDA in RJ depends on supplementary feeding of the bee families. A total of 50 RJ samples were analyzed. The data about Bulgarian royal jelly is not available, therefore the results presented in this study could be considered as a pioneer study for 10- HDA content in Bulgarian royal jelly.