After the very successful Fifth ROOT Users Workshop in February 2004 at SLAC we are happy to annouce the Sixth ROOT Users Workshop, to be held at CERN the 28th, 29th and 30th of September 2005. As the use of ROOT continues to grow at a rapid pace it remains important to continue meeting at a regular basis to discuss technical issues, share ideas and plan directions for future development. The main workshop topics are the use of ROOT as a general framework, feedback from experiments, progress with object persistency, merge with SEAL Reflex, progress with the new version of CINT, progress with the Python interface, what is new with the Math libraries, distributed Data Analysis with PROOF, progress with GUIs and graphics, progress with the new GL viewer, progress with the Geometry classes. And much more. The workshop slides are available at here. We also invite participants to come with questions, comments, proposals to be discussed in a special Q&A session.