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Ultra-cool dwarfs (UCDs) serve as a link between the lowest mass stars and the brown dwarfs. Gaia DR2 revealed thousands of ultra-cool dwarfs not identified as such before. In this work, we searched for companions to those in the Gaia catalogue, from their common proper motions and parallaxes. We found about 1,700 stars in multiple systems out of the original 16,500 sample. Among the companions, there are several tens of young stellar objects and white dwarfs, but also new UCD candidates. Such a sample can be used to better understand the binary properties of UCDs and to better characterize the physics of UCDs thanks to the easier characterization of higher mass companions.