The complex and multi-phase nature of gas outflows is one of the properties highlighted by the work in recent years on AGN-driven outflows. In particular, the cold gas is found to play a more important role than previously expected. Surprisingly, HI has been shown to be a good tracer of fast outflows. In radio AGN, we can trace these outflows by looking at HI in absorption. I will present the results from a survey (done with the Westerbork Synthesis Radio Telescope) of radio sources up to z = 0.2, which has allowed us to explore, for the first time in a systematic way, the occurrence of HI outflows. A number of new cases have been found, showing outflow velocity up to about 1000 km/s. We have followed up some interesting cases with HI obser...