This fourth edition of the conference focused mainly on noise and fluctuations at the nanometer scale in electron devices, bio-materials, and mesoscopic systems. Since the first conference, the aim of the UPoN conferences is to provide a forum for researchers working on noise and fluctuations, where they can present and discuss their scientific problems with particular attention to those which resist solutions. Topics include: Theoretical frontiers on noise and fluctuations; experimental frontiers on noise and fluctuations; enhanced and suppressed shot noise; noise and coherence; noise and chaos; constructive role of noise; noise in biological systems; noise in devices; and noise in complex systems and non-Gaussian fluctuations.